The emergence of next generation networks(NextG),including 5G and beyond,is reshaping the technological landscape of cellular and mobile networks.These networks are sufficiently scaled to interconnect billions of user...The emergence of next generation networks(NextG),including 5G and beyond,is reshaping the technological landscape of cellular and mobile networks.These networks are sufficiently scaled to interconnect billions of users and devices.Researchers in academia and industry are focusing on technological advancements to achieve highspeed transmission,cell planning,and latency reduction to facilitate emerging applications such as virtual reality,the metaverse,smart cities,smart health,and autonomous vehicles.NextG continuously improves its network functionality to support these applications.Multiple input multiple output(MIMO)technology offers spectral efficiency,dependability,and overall performance in conjunctionwithNextG.This article proposes a secure channel estimation technique in MIMO topology using a norm-estimation model to provide comprehensive insights into protecting NextG network components against adversarial attacks.The technique aims to create long-lasting and secure NextG networks using this extended approach.The viability of MIMO applications and modern AI-driven methodologies to combat cybersecurity threats are explored in this research.Moreover,the proposed model demonstrates high performance in terms of reliability and accuracy,with a 20%reduction in the MalOut-RealOut-Diff metric compared to existing state-of-the-art techniques.展开更多
Waveform generation and digitization play essential roles in numerous physics experiments.In traditional distributed systems for large-scale experiments,each frontend node contains an FPGA for data preprocessing,which...Waveform generation and digitization play essential roles in numerous physics experiments.In traditional distributed systems for large-scale experiments,each frontend node contains an FPGA for data preprocessing,which interfaces with various data converters and exchanges data with a backend central processor.However,the streaming readout architecture has become a new paradigm for several experiments benefiting from advancements in data transmission and computing technologies.This paper proposes a scalable distributed waveform generation and digitization system that utilizes fiber optical connections for data transmission between frontend nodes and a central processor.By utilizing transparent transmission on top of the data link layer,the clock and data ports of the converters in the frontend nodes are directly mapped to the FPGA firmware at the backend.This streaming readout architecture reduces the complexity of frontend development and maintains the data conversion in proximity to the detector.Each frontend node uses a local clock for waveform digitization.To translate the timing information of events in each channel into the system clock domain within the backend central processing FPGA,a novel method is proposed and evaluated using a demonstrator system.展开更多
As a form of discrete representation learning,Vector Quantized Variational Autoencoders(VQ-VAE)have increasingly been applied to generative and multimodal tasks due to their ease of embedding and representative capaci...As a form of discrete representation learning,Vector Quantized Variational Autoencoders(VQ-VAE)have increasingly been applied to generative and multimodal tasks due to their ease of embedding and representative capacity.However,existing VQ-VAEs often perform quantization in the spatial domain,ignoring global structural information and potentially suffering from codebook collapse and information coupling issues.This paper proposes a frequency quantized variational autoencoder(FQ-VAE)to address these issues.The proposed method transforms image features into linear combinations in the frequency domain using a 2D fast Fourier transform(2D-FFT)and performs adaptive quantization on these frequency components to preserve image’s global relationships.The codebook is dynamically optimized to avoid collapse and information coupling issue by considering the usage frequency and dependency of code vectors.Furthermore,we introduce a post-processing module based on graph convolutional networks to further improve reconstruction quality.Experimental results on four public datasets demonstrate that the proposed method outperforms state-of-the-art approaches in terms of Structural Similarity Index(SSIM),Learned Perceptual Image Patch Similarity(LPIPS),and Reconstruction Fréchet Inception Distance(rFID).In the experiments on the CIFAR-10 dataset,compared to the baselinemethod VQ-VAE,the proposedmethod improves the abovemetrics by 4.9%,36.4%,and 52.8%,respectively.展开更多
In this study,the power generation difference between the east-west and the north-south orientation of the vertically installed heterojunction solar cell(HJT)modules was deeply discussed.East-west oriented HJT module ...In this study,the power generation difference between the east-west and the north-south orientation of the vertically installed heterojunction solar cell(HJT)modules was deeply discussed.East-west oriented HJT module has 30%higher power generation,especially in desert photovoltaic(PV)with a bimodal distribution.While the south-north one has a single peak,the same as normal PV modules.Vertical power generation technology of HJT also has less land occupation,which is of great significance for optimizing the design of photovoltaic systems.展开更多
Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination.However,due to the influence of latent heat and condensation efficiency,the water yi...Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination.However,due to the influence of latent heat and condensation efficiency,the water yield from solar-driven interface evaporation remains insufficient,posing a significant challenge that requires resolution.In this work,we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive desalination.By utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity,the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m^(-2)h^(-1)for condensate water yield under one-sun irradiation.Additionally,the device exhibited a salt adsorption capacity of up to48 mg g^(-1)and a salt adsorption rate of 2.1 mg g^(-1)min-1.In addition,the salt adsorption capacity increased by approximately 32%under one-sun irradiation.Furthermore,photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical calculations.Theoretical calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range,improve photothermal conversion performance,and stimulate more photoelectrons to participate in capacitive desalination.Concurrently,the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid interface.This work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.展开更多
Generation of good-quality distractors is a key and time-consuming task associated withmultiple-choice questions(MCQs),one of the assessment items that have dominated the educational field for years.Recent advances in...Generation of good-quality distractors is a key and time-consuming task associated withmultiple-choice questions(MCQs),one of the assessment items that have dominated the educational field for years.Recent advances in language models and architectures present an opportunity for helping teachers to generate and update these elements to the required speed and scale of widespread increase in online education.This study focuses on a text-to-text approach for joints generation of distractors for MCQs,where the context,question and correct answer are used as input,while the set of distractors corresponds to the output,allowing the generation of three distractors in a singlemodel inference.By fine-tuning FlanT5 models and LongT5 with TGlobal attention using a RACE-based dataset,the potential of this approach is explored,demonstrating an improvement in the BLEU and ROUGE-L metrics when compared to previous works and a GPT-3.5 baseline.Additionally,BERTScore is introduced in the evaluation,showing that the fine-tuned models generate distractors semantically close to the reference,but the GPT-3.5 baseline still outperforms in this area.A tendency toward duplicating distractors is noted,although models fine-tuned with Low-Rank Adaptation(LoRA)and 4-bit quantization showcased a significant reduction in duplicated distractors.展开更多
Defective phononic crystals(PnCs)have enabled spatial localization and quantitative amplification of elastic wave energy.Most previous research has focused on applications such as narrow-bandpass filters,ultrasonic se...Defective phononic crystals(PnCs)have enabled spatial localization and quantitative amplification of elastic wave energy.Most previous research has focused on applications such as narrow-bandpass filters,ultrasonic sensors,and piezoelectric energy harvesters,typically operating under the assumption of an external elastic wave incidence.Recently,a novel approach that uses defective PnCs as ultrasonic actuators to generate amplified waves has emerged.However,the existing studies are limited to the generation of either longitudinal or bending waves,with no research addressing the concurrent generation of both.Hence,this paper proposes a straightforward methodology for the concurrent generation and amplification of both wave types utilizing defect modes at independent defect-band frequencies.Bimorph piezoelectric elements are attached to the defect,with each element connected to independent external voltage sources.By precisely adjusting the magnitude and temporal phase differences between the voltage sources,concurrently amplified wave generation is achieved.The paper highlights the advantages of the proposed analytical model.This model is both computationally time-efficient and accurate,in comparison with the COMSOL simulation results.For instance,in case studies,the analytical model reduces the computational time from one hour to mere seconds,while maintaining acceptable error rates of 1%in peak frequencies.This concurrent wave-generation methodology opens new avenues for applications in rotating machinery fault diagnosis,structural health monitoring,and medical imaging.展开更多
We experimentally analyze the effect of the optical power on the time delay signature identification and the random bit generation in chaotic semiconductor laser with optical feedback.Due to the inevitable noise durin...We experimentally analyze the effect of the optical power on the time delay signature identification and the random bit generation in chaotic semiconductor laser with optical feedback.Due to the inevitable noise during the photoelectric detection and analog-digital conversion,the varying of output optical power would change the signal to noise ratio,then impact time delay signature identification and the random bit generation.Our results show that,when the optical power is less than-14 dBm,with the decreasing of the optical power,the actual identified time delay signature degrades and the entropy of the chaotic signal increases.Moreover,the extracted random bit sequence with lower optical power is more easily pass through the randomness testing.展开更多
The physical layer key generation technique provides an efficient method,which utilizes the natural dynamics of wireless channel.However,there are some extremely challenging security scenarios such as static or quasi-...The physical layer key generation technique provides an efficient method,which utilizes the natural dynamics of wireless channel.However,there are some extremely challenging security scenarios such as static or quasi-static environment,which lead to the low randomness of generated keys.Meanwhile,the coefficients of the static channel may be dropped into the guard space and discarded by the quantization approach,which causes low key generation rate.To tackle these issues,we propose a random coefficient-moving product based wireless key generation scheme(RCMP-WKG),where new random resources with remarkable fluctuations can be obtained by applying random coefficient and by moving product on the legitimate nodes.Furthermore,appropriate quantization approaches are used to increase the key generation rate.Moreover,the security of our proposed scheme is evaluated by analyzing different attacks and the eavesdropper’s mean square error(MSE).The simulation results reveal that the proposed scheme can achieve better performances in key capacity,key inconsistency rate(KIR)and key generation rate(KGR)compared with the prior works in static environment.Besides,the proposed scheme can deteriorate the MSE performance of the eavesdropper and improve the key generation performance of legitimate nodes by controlling the length of the moving product.展开更多
The heterostructures incorporated with two or more distinctive two-dimensional(2D)materials have attracted great attention be-cause they could give rise to enhanced prop-erty in comparison with their individual counte...The heterostructures incorporated with two or more distinctive two-dimensional(2D)materials have attracted great attention be-cause they could give rise to enhanced prop-erty in comparison with their individual counterparts.Here,a water-assisted two-step rapid physical vapor deposition(rPVD)method was explored and used to synthesize Bi_(2)Te_(3)-Sb_(2)Te_(3)lateral het-erostructures(LHS)successfully.The Bi_(2)Te_(3)-Sb_(2)Te_(3)LHS is in nearly uniform size,and grows along three particular orientations with the intersection angles of 120°.Inter-estingly,we found that the water molecules play a significant role in determining the growth orientation,namely whether it will grow along the vertical or lateral direction in 2D structure.Hence,a growth mechanism of LHS based on the water-assisted two-step rPVD was present,which can be used as a general strategy and extended to the growth of other 2D heterostruc-tures or homostructures,such as SnS-SnSe LHS and SnS-SnS lateral homostructures.Fur-thermore,the second-harmonic generation intensity of the Bi_(2)Te_(3)-Sb_(2)Te_(3)LHS is much stronger than that of the Bi_(2)Te_(3)/Sb_(2)Te_(3)vertical heterostructures(VHS).This work opens a new approach for the synthesis of water-assisted lateral 2D heterostructures or homostruc-tures and offers a new method to enhance the second-harmonic generation properties of topo-logical insulating materials.展开更多
Realistic urban scene generation has been extensively studied for the sake of the development of autonomous vehicles. However, the research has primarily focused on the synthesis of vehicles and pedestrians, while the...Realistic urban scene generation has been extensively studied for the sake of the development of autonomous vehicles. However, the research has primarily focused on the synthesis of vehicles and pedestrians, while the generation of cyclists is rarely presented due to its complexity. This paper proposes a perspective-aware and realistic cyclist generation method via object retrieval. Images, semantic maps, and depth labels of objects are first collected from existing datasets, categorized by class and perspective, and calculated by an algorithm newly designed according to imaging principles. During scene generation, objects with the desired class and perspective are retrieved from the collection and inserted into the background, which is then sent to the modified 2D synthesis model to generate images. This pipeline introduces a perspective computing method, utilizes object retrieval to control the perspective accurately, and modifies a diffusion model to achieve high fidelity. Experiments show that our proposal gets a 2.36 Fréchet Inception Distance, which is lower than the competitive methods, indicating a superior realistic expression ability. When these images are used for augmentation in the semantic segmentation task, the performance of ResNet-50 on the target class can be improved by 4.47%. These results demonstrate that the proposed method can be used to generate cyclists in corner cases to augment model training data, further enhancing the perception capability of autonomous vehicles and improving the safety performance of autonomous driving technology.展开更多
Two types of bound states in continuum(BICs),symmetry-protected and Brillouin zone folding driven,are identified in hollow Si nanorod arrays.By modulating the direction and distance of the air holes from the center of...Two types of bound states in continuum(BICs),symmetry-protected and Brillouin zone folding driven,are identified in hollow Si nanorod arrays.By modulating the direction and distance of the air holes from the center of the nanorods,it is possible to achieve either a single quasi-BIC or three quasi-BICs.The transmission spectra exhibit ultra-narrow lines,and the quasi-BICs demonstrate ultra-high Q factors.Additionally,efficient third-harmonic generation occurs at low pump intensities.The results indicate that the proposed nanostructures of two types of BICs with a flexible modulation hold great potential applications for nonlinear photonic devices.展开更多
Unlike other major crops,little research has been performed on tomato to reduce the generation time for speed breeding.We evaluated several agronomic treatments to reduce the generation time of tomato in the‘M82'...Unlike other major crops,little research has been performed on tomato to reduce the generation time for speed breeding.We evaluated several agronomic treatments to reduce the generation time of tomato in the‘M82'(determinate)and‘Moneymaker'(indeterminate)varieties and evaluated the best combination in conjunction with embryo rescue.Five container sizes with volumes of 0.2 L(XS),0.45 L(S),0.8 L(M),1.3 L(L),and6 L(XL),were evaluated in the first experiment under the autumn cycle.We found that plants grown in XL containers exhibited better development and required less time from sowing to anthesis(DSA)and from anthesis to fruit ripening(DAR).In the second experiment,using XL containers in the autumn-winter cycle,we evaluated the effects of cold priming at the cotyledonary stage,water stress,P supplementation,and K supplementation on generation time.Compared to the control,we found that cold priming significantly reduced the number of leaves,plant height to first the inflorescence,and DSA(2.7 d),whereas K supplementation reduced the DAR(8.8 d).In contrast,water stress and P supplementation did not significantly affect any of the measured traits like DAR,DSA or fruit set.To validate these data,in a third experiment with XL containers in the spring-summer cycle,the combination of cold priming and K supplementation was tested,confirming the significant effect of this combination on the reduction of generation time(2.9 d for DSA and 3.9 d for DAR)compared to the control.Embryo rescue during the cell expansion cycle(average of 22.0 d and 23.3 d after anthesis for‘M82'and‘Moneymaker',respectively)allowed the shortening of the generation time by 8.7 d in‘M82'and 11.6 d in‘Moneymaker'compared to the in planta fruit ripening.The combination of agronomic treatments with embryo rescue can effectively increase the number of generations per year from three to four for speed breeding of tomato.展开更多
This paper proposes a concurrent neural network model to mitigate non-linear distortion in power amplifiers using a basis function generation approach.The model is designed using polynomial expansion and comprises a f...This paper proposes a concurrent neural network model to mitigate non-linear distortion in power amplifiers using a basis function generation approach.The model is designed using polynomial expansion and comprises a feedforward neural network(FNN)and a convolutional neural network(CNN).The proposed model takes the basic elements that form the bases as input,defined by the generalized memory polynomial(GMP)and dynamic deviation reduction(DDR)models.The FNN generates the basis function and its output represents the basis values,while the CNN generates weights for the corresponding bases.Through the concurrent training of FNN and CNN,the hidden layer coefficients are updated,and the complex multiplication of their outputs yields the trained in-phase/quadrature(I/Q)signals.The proposed model was trained and tested using 300 MHz and 400 MHz broadband data in an orthogonal frequency division multiplexing(OFDM)communication system.The results show that the model achieves an adjacent channel power ratio(ACPR)of less than-48 d B within a 100 MHz integral bandwidth for both the training and test datasets.展开更多
Solar-driven interfacial evaporation is one of the most attractive approaches to addressing the global freshwater shortage.However,achieving an integrated high evaporation rate,salt harvesting,and multifunctionality i...Solar-driven interfacial evaporation is one of the most attractive approaches to addressing the global freshwater shortage.However,achieving an integrated high evaporation rate,salt harvesting,and multifunctionality in evaporator is still a crucial challenge.Here,a novel composite membrane with biomimetic micronanostructured superhydrophobic surface is designed via ultrafast laser etching technology.Attractively,the double-transition-metal(V_(1/2)Mo_(1/2))_(2)CT_(x)MXene nanomaterials as a photothermal layer,exhibiting the enhanced photothermal conversion performance due to elevated joint densities of states,which enables high populations of photoexcited carrier relaxation and heat release,provides a new insight into the photothermal conversion mechanism for multiple principal element MXene.Hence,the(V_(1/2)Mo_(1/2))_(2)CT_(x)MXene-200 composite membrane can achieve a high evaporation rate of 2.23 kg m^(−2)h^(−1)under one sun,owing to the enhanced“light trap”effect,photothermal conversion,and high-throughput water transfer.Synergetically,the membrane can induce the directed precipitation of salt at the membrane edge,thus enabling salt harvesting for recycling and zero-emission of brine water.Moreover,the composite membrane is endowed with excellent multifunctionality of anti-/de-icing,anti-fouling,and antibacterial,overcoming the disadvantage that versatility is difficult to be compatible.Therefore,the evaporator and the promising strategy hold great potential for the practical application of solar evaporation.展开更多
With the continuous adjustment of the energy structure,photovoltaic(PV)power generation projects are increasing,playing a crucial role in promoting the application of clean energy.However,the current audit of complete...With the continuous adjustment of the energy structure,photovoltaic(PV)power generation projects are increasing,playing a crucial role in promoting the application of clean energy.However,the current audit of completed final accounts for photovoltaic power generation projects faces many challenges,such as incomplete institutional processes,scattered archive management materials,inadequate digital intelligence systems,and insufficient analysis of final account amounts.Based on this,this article aims to deeply analyze these issues and propose targeted audit suggestions to standardize the construction and audit work of photovoltaic power generation projects and promote the sustainable and healthy development of the photovoltaic power generation business.展开更多
This article comments on the letter by Lowell et al,which addresses the next generation of combination therapy for inflammatory bowel disease(IBD).As the understanding of the pathogenesis of IBD continues to improve,t...This article comments on the letter by Lowell et al,which addresses the next generation of combination therapy for inflammatory bowel disease(IBD).As the understanding of the pathogenesis of IBD continues to improve,treatment strategies are evolving rapidly.The letter examines the current status and future directions of combination therapy for IBD,focusing on approaches that combine biologics with immunomodulators and the emerging dual-biologic therapy(DBT).The traditional combination of biologics and immunomodulators has demonstra-ted preliminary efficacy by enhancing the effects of biologics through immunomo-dulation.However,concerns regarding long-term safety warrant careful evalua-tion.Recent trials,including DUET-Crohn's disease and DUET-ulcerative colitis,have shown promising potential for the broader adoption of DBT.Nevertheless,comprehensive data on efficacy and safety,as well as the effective integration of supportive treatments,remain essential to establish new paradigms for the next generation of IBD care.展开更多
In the context of power generation companies, vast amounts of specialized data and expert knowledge have been accumulated. However, challenges such as data silos and fragmented knowledge hinder the effective utilizati...In the context of power generation companies, vast amounts of specialized data and expert knowledge have been accumulated. However, challenges such as data silos and fragmented knowledge hinder the effective utilization of this information. This study proposes a novel framework for intelligent Question-and-Answer (Q&A) systems based on Retrieval-Augmented Generation (RAG) to address these issues. The system efficiently acquires domain-specific knowledge by leveraging external databases, including Relational Databases (RDBs) and graph databases, without additional fine-tuning for Large Language Models (LLMs). Crucially, the framework integrates a Dynamic Knowledge Base Updating Mechanism (DKBUM) and a Weighted Context-Aware Similarity (WCAS) method to enhance retrieval accuracy and mitigate inherent limitations of LLMs, such as hallucinations and lack of specialization. Additionally, the proposed DKBUM dynamically adjusts knowledge weights within the database, ensuring that the most recent and relevant information is utilized, while WCAS refines the alignment between queries and knowledge items by enhanced context understanding. Experimental validation demonstrates that the system can generate timely, accurate, and context-sensitive responses, making it a robust solution for managing complex business logic in specialized industries.展开更多
The transition to renewable energy sources has elevated the importance of SIBs(SIBs)as cost-effective alternatives to lithium-ion batteries(LIBs)for large-scale energy storage.This review examines the mechanisms of ga...The transition to renewable energy sources has elevated the importance of SIBs(SIBs)as cost-effective alternatives to lithium-ion batteries(LIBs)for large-scale energy storage.This review examines the mechanisms of gas generation in SIBs,identifying sources from cathode materials,anode materials,and electrolytes,which pose safety risks like swelling,leakage,and explosions.Gases such as CO_(2),H_(2),and O_(2) primarily arise from the instability of cathode materials,side reactions between electrode and electrolyte,and electrolyte decomposition under high temperatures or voltages.Enhanced mitigation strategies,encompassing electrolyte design,buffer layer construction,and electrode material optimization,are deliberated upon.Accordingly,subsequent research endeavors should prioritize long-term high-precision gas detection to bolster the safety and performance of SIBs,thereby fortifying their commercial viability and furnishing dependable solutions for large-scale energy storage and electric vehicles.展开更多
Wireless communication systems that incorporate digital twin(DT)alongside artificial intelligence(AI)are expected to transform 6G networks by providing advanced features for predictive modeling and decision making.The...Wireless communication systems that incorporate digital twin(DT)alongside artificial intelligence(AI)are expected to transform 6G networks by providing advanced features for predictive modeling and decision making.The key component is the creation of DT channels,which form the basis for upcoming applications.However,the existing work of channel predictive generation only considers time dimension,distribution-oriented or multi-step slidingwindow prediction schemes,which is not accurate and efficient for real-time DT communication systems.Therefore,we propose the wireless channel generative adversarial network(WCGAN)to tackle the issue of generating authentic long-batch channels for DT applications.The generator based on convolutional neural networks(CNN)extracts features from both the time and frequency domains to better capture the correlation.The loss function is designed to ensure that the generated channels consistently match the physical channels over an extended period while sharing the same probability distributions.Meanwhile,the accumulating error from the slicing window has been alleviated.The simulation demonstrates that an accurate and efficient DT channel can be generated by employing our proposed WCGAN in various scenarios.展开更多
基金funding from King Saud University through Researchers Supporting Project number(RSP2024R387),King Saud University,Riyadh,Saudi Arabia.
文摘The emergence of next generation networks(NextG),including 5G and beyond,is reshaping the technological landscape of cellular and mobile networks.These networks are sufficiently scaled to interconnect billions of users and devices.Researchers in academia and industry are focusing on technological advancements to achieve highspeed transmission,cell planning,and latency reduction to facilitate emerging applications such as virtual reality,the metaverse,smart cities,smart health,and autonomous vehicles.NextG continuously improves its network functionality to support these applications.Multiple input multiple output(MIMO)technology offers spectral efficiency,dependability,and overall performance in conjunctionwithNextG.This article proposes a secure channel estimation technique in MIMO topology using a norm-estimation model to provide comprehensive insights into protecting NextG network components against adversarial attacks.The technique aims to create long-lasting and secure NextG networks using this extended approach.The viability of MIMO applications and modern AI-driven methodologies to combat cybersecurity threats are explored in this research.Moreover,the proposed model demonstrates high performance in terms of reliability and accuracy,with a 20%reduction in the MalOut-RealOut-Diff metric compared to existing state-of-the-art techniques.
基金supported by the National Key Research and Development Program of China(No.2022YFA1604703)the National Natural Science Foundation of China(No.12375189)the National Key Research and Development Program of China(No.2021YFA1601300)。
文摘Waveform generation and digitization play essential roles in numerous physics experiments.In traditional distributed systems for large-scale experiments,each frontend node contains an FPGA for data preprocessing,which interfaces with various data converters and exchanges data with a backend central processor.However,the streaming readout architecture has become a new paradigm for several experiments benefiting from advancements in data transmission and computing technologies.This paper proposes a scalable distributed waveform generation and digitization system that utilizes fiber optical connections for data transmission between frontend nodes and a central processor.By utilizing transparent transmission on top of the data link layer,the clock and data ports of the converters in the frontend nodes are directly mapped to the FPGA firmware at the backend.This streaming readout architecture reduces the complexity of frontend development and maintains the data conversion in proximity to the detector.Each frontend node uses a local clock for waveform digitization.To translate the timing information of events in each channel into the system clock domain within the backend central processing FPGA,a novel method is proposed and evaluated using a demonstrator system.
基金supported by the Interdisciplinary project of Dalian University DLUXK-2023-ZD-001.
文摘As a form of discrete representation learning,Vector Quantized Variational Autoencoders(VQ-VAE)have increasingly been applied to generative and multimodal tasks due to their ease of embedding and representative capacity.However,existing VQ-VAEs often perform quantization in the spatial domain,ignoring global structural information and potentially suffering from codebook collapse and information coupling issues.This paper proposes a frequency quantized variational autoencoder(FQ-VAE)to address these issues.The proposed method transforms image features into linear combinations in the frequency domain using a 2D fast Fourier transform(2D-FFT)and performs adaptive quantization on these frequency components to preserve image’s global relationships.The codebook is dynamically optimized to avoid collapse and information coupling issue by considering the usage frequency and dependency of code vectors.Furthermore,we introduce a post-processing module based on graph convolutional networks to further improve reconstruction quality.Experimental results on four public datasets demonstrate that the proposed method outperforms state-of-the-art approaches in terms of Structural Similarity Index(SSIM),Learned Perceptual Image Patch Similarity(LPIPS),and Reconstruction Fréchet Inception Distance(rFID).In the experiments on the CIFAR-10 dataset,compared to the baselinemethod VQ-VAE,the proposedmethod improves the abovemetrics by 4.9%,36.4%,and 52.8%,respectively.
文摘In this study,the power generation difference between the east-west and the north-south orientation of the vertically installed heterojunction solar cell(HJT)modules was deeply discussed.East-west oriented HJT module has 30%higher power generation,especially in desert photovoltaic(PV)with a bimodal distribution.While the south-north one has a single peak,the same as normal PV modules.Vertical power generation technology of HJT also has less land occupation,which is of great significance for optimizing the design of photovoltaic systems.
基金financially supported by research grants from the Natural Science Foundation of China(52173235,22265010,12204071,62074022)National Key Research and Development Program of China(2022YFB3803300)+2 种基金Youth Talent Support Program of Chongqing(CQYC2021059206)Hainan Province Science and Technology Special Fund(ZDYF2024SHFZ038)Science and Technology Innovation and Improving Project of Army Medical University(No.2021XJS24)。
文摘Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination.However,due to the influence of latent heat and condensation efficiency,the water yield from solar-driven interface evaporation remains insufficient,posing a significant challenge that requires resolution.In this work,we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive desalination.By utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity,the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m^(-2)h^(-1)for condensate water yield under one-sun irradiation.Additionally,the device exhibited a salt adsorption capacity of up to48 mg g^(-1)and a salt adsorption rate of 2.1 mg g^(-1)min-1.In addition,the salt adsorption capacity increased by approximately 32%under one-sun irradiation.Furthermore,photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical calculations.Theoretical calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range,improve photothermal conversion performance,and stimulate more photoelectrons to participate in capacitive desalination.Concurrently,the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid interface.This work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.
基金supported by the Universidad de Alcalá(UAH)under Grant PIUAH21/IA-010Comunidad Autonóma de Madrid under Grant CM/JIN/2021-034.
文摘Generation of good-quality distractors is a key and time-consuming task associated withmultiple-choice questions(MCQs),one of the assessment items that have dominated the educational field for years.Recent advances in language models and architectures present an opportunity for helping teachers to generate and update these elements to the required speed and scale of widespread increase in online education.This study focuses on a text-to-text approach for joints generation of distractors for MCQs,where the context,question and correct answer are used as input,while the set of distractors corresponds to the output,allowing the generation of three distractors in a singlemodel inference.By fine-tuning FlanT5 models and LongT5 with TGlobal attention using a RACE-based dataset,the potential of this approach is explored,demonstrating an improvement in the BLEU and ROUGE-L metrics when compared to previous works and a GPT-3.5 baseline.Additionally,BERTScore is introduced in the evaluation,showing that the fine-tuned models generate distractors semantically close to the reference,but the GPT-3.5 baseline still outperforms in this area.A tendency toward duplicating distractors is noted,although models fine-tuned with Low-Rank Adaptation(LoRA)and 4-bit quantization showcased a significant reduction in duplicated distractors.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea,funded by the Ministry of Education(No.2022R1I1A1A01056406)。
文摘Defective phononic crystals(PnCs)have enabled spatial localization and quantitative amplification of elastic wave energy.Most previous research has focused on applications such as narrow-bandpass filters,ultrasonic sensors,and piezoelectric energy harvesters,typically operating under the assumption of an external elastic wave incidence.Recently,a novel approach that uses defective PnCs as ultrasonic actuators to generate amplified waves has emerged.However,the existing studies are limited to the generation of either longitudinal or bending waves,with no research addressing the concurrent generation of both.Hence,this paper proposes a straightforward methodology for the concurrent generation and amplification of both wave types utilizing defect modes at independent defect-band frequencies.Bimorph piezoelectric elements are attached to the defect,with each element connected to independent external voltage sources.By precisely adjusting the magnitude and temporal phase differences between the voltage sources,concurrently amplified wave generation is achieved.The paper highlights the advantages of the proposed analytical model.This model is both computationally time-efficient and accurate,in comparison with the COMSOL simulation results.For instance,in case studies,the analytical model reduces the computational time from one hour to mere seconds,while maintaining acceptable error rates of 1%in peak frequencies.This concurrent wave-generation methodology opens new avenues for applications in rotating machinery fault diagnosis,structural health monitoring,and medical imaging.
基金Project supported in part by the National Natural Science Foundation of China(Grant Nos.62005129 and 62175116)。
文摘We experimentally analyze the effect of the optical power on the time delay signature identification and the random bit generation in chaotic semiconductor laser with optical feedback.Due to the inevitable noise during the photoelectric detection and analog-digital conversion,the varying of output optical power would change the signal to noise ratio,then impact time delay signature identification and the random bit generation.Our results show that,when the optical power is less than-14 dBm,with the decreasing of the optical power,the actual identified time delay signature degrades and the entropy of the chaotic signal increases.Moreover,the extracted random bit sequence with lower optical power is more easily pass through the randomness testing.
基金supported in part by the National Natural Science Foundation of China(Numbers 62171445,62471477 and 62201592).
文摘The physical layer key generation technique provides an efficient method,which utilizes the natural dynamics of wireless channel.However,there are some extremely challenging security scenarios such as static or quasi-static environment,which lead to the low randomness of generated keys.Meanwhile,the coefficients of the static channel may be dropped into the guard space and discarded by the quantization approach,which causes low key generation rate.To tackle these issues,we propose a random coefficient-moving product based wireless key generation scheme(RCMP-WKG),where new random resources with remarkable fluctuations can be obtained by applying random coefficient and by moving product on the legitimate nodes.Furthermore,appropriate quantization approaches are used to increase the key generation rate.Moreover,the security of our proposed scheme is evaluated by analyzing different attacks and the eavesdropper’s mean square error(MSE).The simulation results reveal that the proposed scheme can achieve better performances in key capacity,key inconsistency rate(KIR)and key generation rate(KGR)compared with the prior works in static environment.Besides,the proposed scheme can deteriorate the MSE performance of the eavesdropper and improve the key generation performance of legitimate nodes by controlling the length of the moving product.
基金supported by the Natural Science Foundation of Fujian Province of China(2022J01646)。
文摘The heterostructures incorporated with two or more distinctive two-dimensional(2D)materials have attracted great attention be-cause they could give rise to enhanced prop-erty in comparison with their individual counterparts.Here,a water-assisted two-step rapid physical vapor deposition(rPVD)method was explored and used to synthesize Bi_(2)Te_(3)-Sb_(2)Te_(3)lateral het-erostructures(LHS)successfully.The Bi_(2)Te_(3)-Sb_(2)Te_(3)LHS is in nearly uniform size,and grows along three particular orientations with the intersection angles of 120°.Inter-estingly,we found that the water molecules play a significant role in determining the growth orientation,namely whether it will grow along the vertical or lateral direction in 2D structure.Hence,a growth mechanism of LHS based on the water-assisted two-step rPVD was present,which can be used as a general strategy and extended to the growth of other 2D heterostruc-tures or homostructures,such as SnS-SnSe LHS and SnS-SnS lateral homostructures.Fur-thermore,the second-harmonic generation intensity of the Bi_(2)Te_(3)-Sb_(2)Te_(3)LHS is much stronger than that of the Bi_(2)Te_(3)/Sb_(2)Te_(3)vertical heterostructures(VHS).This work opens a new approach for the synthesis of water-assisted lateral 2D heterostructures or homostruc-tures and offers a new method to enhance the second-harmonic generation properties of topo-logical insulating materials.
基金supported by the Cultivation Program for Major Scientific Research Projects of Harbin Institute of Technology(ZDXMPY20180109).
文摘Realistic urban scene generation has been extensively studied for the sake of the development of autonomous vehicles. However, the research has primarily focused on the synthesis of vehicles and pedestrians, while the generation of cyclists is rarely presented due to its complexity. This paper proposes a perspective-aware and realistic cyclist generation method via object retrieval. Images, semantic maps, and depth labels of objects are first collected from existing datasets, categorized by class and perspective, and calculated by an algorithm newly designed according to imaging principles. During scene generation, objects with the desired class and perspective are retrieved from the collection and inserted into the background, which is then sent to the modified 2D synthesis model to generate images. This pipeline introduces a perspective computing method, utilizes object retrieval to control the perspective accurately, and modifies a diffusion model to achieve high fidelity. Experiments show that our proposal gets a 2.36 Fréchet Inception Distance, which is lower than the competitive methods, indicating a superior realistic expression ability. When these images are used for augmentation in the semantic segmentation task, the performance of ResNet-50 on the target class can be improved by 4.47%. These results demonstrate that the proposed method can be used to generate cyclists in corner cases to augment model training data, further enhancing the perception capability of autonomous vehicles and improving the safety performance of autonomous driving technology.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12174228 and 12274271)。
文摘Two types of bound states in continuum(BICs),symmetry-protected and Brillouin zone folding driven,are identified in hollow Si nanorod arrays.By modulating the direction and distance of the air holes from the center of the nanorods,it is possible to achieve either a single quasi-BIC or three quasi-BICs.The transmission spectra exhibit ultra-narrow lines,and the quasi-BICs demonstrate ultra-high Q factors.Additionally,efficient third-harmonic generation occurs at low pump intensities.The results indicate that the proposed nanostructures of two types of BICs with a flexible modulation hold great potential applications for nonlinear photonic devices.
基金funded by the European Commission H2020 Research and Innovation Programme through the HARNESSTOM innovation action(Grant No.101000716)Grant CIPROM/2021/020(project SOLECO)funded by Conselleria d’Innovació,Universitats,Ciència i Societat Digital(Generalitat Valenciana,Spain)Pietro Gramazio received a post-doctoral fellowship(Grant No.RYC2021-031999-I)funded by MCIN/AEI/10.13039/501100011033 and by“European Union NextGenerationEU/PRTR”。
文摘Unlike other major crops,little research has been performed on tomato to reduce the generation time for speed breeding.We evaluated several agronomic treatments to reduce the generation time of tomato in the‘M82'(determinate)and‘Moneymaker'(indeterminate)varieties and evaluated the best combination in conjunction with embryo rescue.Five container sizes with volumes of 0.2 L(XS),0.45 L(S),0.8 L(M),1.3 L(L),and6 L(XL),were evaluated in the first experiment under the autumn cycle.We found that plants grown in XL containers exhibited better development and required less time from sowing to anthesis(DSA)and from anthesis to fruit ripening(DAR).In the second experiment,using XL containers in the autumn-winter cycle,we evaluated the effects of cold priming at the cotyledonary stage,water stress,P supplementation,and K supplementation on generation time.Compared to the control,we found that cold priming significantly reduced the number of leaves,plant height to first the inflorescence,and DSA(2.7 d),whereas K supplementation reduced the DAR(8.8 d).In contrast,water stress and P supplementation did not significantly affect any of the measured traits like DAR,DSA or fruit set.To validate these data,in a third experiment with XL containers in the spring-summer cycle,the combination of cold priming and K supplementation was tested,confirming the significant effect of this combination on the reduction of generation time(2.9 d for DSA and 3.9 d for DAR)compared to the control.Embryo rescue during the cell expansion cycle(average of 22.0 d and 23.3 d after anthesis for‘M82'and‘Moneymaker',respectively)allowed the shortening of the generation time by 8.7 d in‘M82'and 11.6 d in‘Moneymaker'compared to the in planta fruit ripening.The combination of agronomic treatments with embryo rescue can effectively increase the number of generations per year from three to four for speed breeding of tomato.
基金supported by ZTE Industry-University-Institute Cooperation Funds under Grant No.HC-CN-20220722010。
文摘This paper proposes a concurrent neural network model to mitigate non-linear distortion in power amplifiers using a basis function generation approach.The model is designed using polynomial expansion and comprises a feedforward neural network(FNN)and a convolutional neural network(CNN).The proposed model takes the basic elements that form the bases as input,defined by the generalized memory polynomial(GMP)and dynamic deviation reduction(DDR)models.The FNN generates the basis function and its output represents the basis values,while the CNN generates weights for the corresponding bases.Through the concurrent training of FNN and CNN,the hidden layer coefficients are updated,and the complex multiplication of their outputs yields the trained in-phase/quadrature(I/Q)signals.The proposed model was trained and tested using 300 MHz and 400 MHz broadband data in an orthogonal frequency division multiplexing(OFDM)communication system.The results show that the model achieves an adjacent channel power ratio(ACPR)of less than-48 d B within a 100 MHz integral bandwidth for both the training and test datasets.
基金supported by the National Natural Science Foundation of China(No.U2106216,52331004)the Natural Science Foundation of Shandong Province(No.ZR2022ZD12)+5 种基金the Key R&D Program of Shandong Province,China(2023ZLGX05,2023CXGC010406)the Taishan Scholarship of Climbing Plan(No.tspd20230603)the Fundamental Research Funds for the Central Universities(202461105)the China Postdoctoral Science Foundation(2023M732677)Shandong Province Postdoctoral Innovation Project(SDCX-ZG-202303086)Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education(LOEC-202309).
文摘Solar-driven interfacial evaporation is one of the most attractive approaches to addressing the global freshwater shortage.However,achieving an integrated high evaporation rate,salt harvesting,and multifunctionality in evaporator is still a crucial challenge.Here,a novel composite membrane with biomimetic micronanostructured superhydrophobic surface is designed via ultrafast laser etching technology.Attractively,the double-transition-metal(V_(1/2)Mo_(1/2))_(2)CT_(x)MXene nanomaterials as a photothermal layer,exhibiting the enhanced photothermal conversion performance due to elevated joint densities of states,which enables high populations of photoexcited carrier relaxation and heat release,provides a new insight into the photothermal conversion mechanism for multiple principal element MXene.Hence,the(V_(1/2)Mo_(1/2))_(2)CT_(x)MXene-200 composite membrane can achieve a high evaporation rate of 2.23 kg m^(−2)h^(−1)under one sun,owing to the enhanced“light trap”effect,photothermal conversion,and high-throughput water transfer.Synergetically,the membrane can induce the directed precipitation of salt at the membrane edge,thus enabling salt harvesting for recycling and zero-emission of brine water.Moreover,the composite membrane is endowed with excellent multifunctionality of anti-/de-icing,anti-fouling,and antibacterial,overcoming the disadvantage that versatility is difficult to be compatible.Therefore,the evaporator and the promising strategy hold great potential for the practical application of solar evaporation.
文摘With the continuous adjustment of the energy structure,photovoltaic(PV)power generation projects are increasing,playing a crucial role in promoting the application of clean energy.However,the current audit of completed final accounts for photovoltaic power generation projects faces many challenges,such as incomplete institutional processes,scattered archive management materials,inadequate digital intelligence systems,and insufficient analysis of final account amounts.Based on this,this article aims to deeply analyze these issues and propose targeted audit suggestions to standardize the construction and audit work of photovoltaic power generation projects and promote the sustainable and healthy development of the photovoltaic power generation business.
基金Supported by the National Natural Science Foundation of China,No.82400591(to Wu FF).
文摘This article comments on the letter by Lowell et al,which addresses the next generation of combination therapy for inflammatory bowel disease(IBD).As the understanding of the pathogenesis of IBD continues to improve,treatment strategies are evolving rapidly.The letter examines the current status and future directions of combination therapy for IBD,focusing on approaches that combine biologics with immunomodulators and the emerging dual-biologic therapy(DBT).The traditional combination of biologics and immunomodulators has demonstra-ted preliminary efficacy by enhancing the effects of biologics through immunomo-dulation.However,concerns regarding long-term safety warrant careful evalua-tion.Recent trials,including DUET-Crohn's disease and DUET-ulcerative colitis,have shown promising potential for the broader adoption of DBT.Nevertheless,comprehensive data on efficacy and safety,as well as the effective integration of supportive treatments,remain essential to establish new paradigms for the next generation of IBD care.
文摘In the context of power generation companies, vast amounts of specialized data and expert knowledge have been accumulated. However, challenges such as data silos and fragmented knowledge hinder the effective utilization of this information. This study proposes a novel framework for intelligent Question-and-Answer (Q&A) systems based on Retrieval-Augmented Generation (RAG) to address these issues. The system efficiently acquires domain-specific knowledge by leveraging external databases, including Relational Databases (RDBs) and graph databases, without additional fine-tuning for Large Language Models (LLMs). Crucially, the framework integrates a Dynamic Knowledge Base Updating Mechanism (DKBUM) and a Weighted Context-Aware Similarity (WCAS) method to enhance retrieval accuracy and mitigate inherent limitations of LLMs, such as hallucinations and lack of specialization. Additionally, the proposed DKBUM dynamically adjusts knowledge weights within the database, ensuring that the most recent and relevant information is utilized, while WCAS refines the alignment between queries and knowledge items by enhanced context understanding. Experimental validation demonstrates that the system can generate timely, accurate, and context-sensitive responses, making it a robust solution for managing complex business logic in specialized industries.
基金financial support of Shenzhen Science and Technology Program(No.KJZD20230923115005009)Xiangjiang Lab(22XJ01007)+3 种基金National Natural Science Foundation(NNSF)of China(No.52202269)Shenzhen Science and Technology program(No.20220810155330003)Shenzhen Science and Technology Program(NO.KJZD20230923115005009)Project of Department of Education of Guangdong Province(No.2022ZDZX3018).
文摘The transition to renewable energy sources has elevated the importance of SIBs(SIBs)as cost-effective alternatives to lithium-ion batteries(LIBs)for large-scale energy storage.This review examines the mechanisms of gas generation in SIBs,identifying sources from cathode materials,anode materials,and electrolytes,which pose safety risks like swelling,leakage,and explosions.Gases such as CO_(2),H_(2),and O_(2) primarily arise from the instability of cathode materials,side reactions between electrode and electrolyte,and electrolyte decomposition under high temperatures or voltages.Enhanced mitigation strategies,encompassing electrolyte design,buffer layer construction,and electrode material optimization,are deliberated upon.Accordingly,subsequent research endeavors should prioritize long-term high-precision gas detection to bolster the safety and performance of SIBs,thereby fortifying their commercial viability and furnishing dependable solutions for large-scale energy storage and electric vehicles.
文摘Wireless communication systems that incorporate digital twin(DT)alongside artificial intelligence(AI)are expected to transform 6G networks by providing advanced features for predictive modeling and decision making.The key component is the creation of DT channels,which form the basis for upcoming applications.However,the existing work of channel predictive generation only considers time dimension,distribution-oriented or multi-step slidingwindow prediction schemes,which is not accurate and efficient for real-time DT communication systems.Therefore,we propose the wireless channel generative adversarial network(WCGAN)to tackle the issue of generating authentic long-batch channels for DT applications.The generator based on convolutional neural networks(CNN)extracts features from both the time and frequency domains to better capture the correlation.The loss function is designed to ensure that the generated channels consistently match the physical channels over an extended period while sharing the same probability distributions.Meanwhile,the accumulating error from the slicing window has been alleviated.The simulation demonstrates that an accurate and efficient DT channel can be generated by employing our proposed WCGAN in various scenarios.
