Rail surface damage is a critical component of high-speed railway infrastructure,directly affecting train operational stability and safety.Existing methods face limitations in accuracy and speed for small-sample,multi...Rail surface damage is a critical component of high-speed railway infrastructure,directly affecting train operational stability and safety.Existing methods face limitations in accuracy and speed for small-sample,multi-category,and multi-scale target segmentation tasks.To address these challenges,this paper proposes Pyramid-MixNet,an intelligent segmentation model for high-speed rail surface damage,leveraging dataset construction and expansion alongside a feature pyramid-based encoder-decoder network with multi-attention mechanisms.The encoding net-work integrates Spatial Reduction Masked Multi-Head Attention(SRMMHA)to enhance global feature extraction while reducing trainable parameters.The decoding network incorporates Mix-Attention(MA),enabling multi-scale structural understanding and cross-scale token group correlation learning.Experimental results demonstrate that the proposed method achieves 62.17%average segmentation accuracy,80.28%Damage Dice Coefficient,and 56.83 FPS,meeting real-time detection requirements.The model’s high accuracy and scene adaptability significantly improve the detection of small-scale and complex multi-scale rail damage,offering practical value for real-time monitoring in high-speed railway maintenance systems.展开更多
The encoding/decoding scheme based on Fiber Bragg Grating (FBG) for Optical Code Division Multiple Access (OCDMA) system is analyzed and the whole process from transmitting end to receiving end is researched in detail...The encoding/decoding scheme based on Fiber Bragg Grating (FBG) for Optical Code Division Multiple Access (OCDMA) system is analyzed and the whole process from transmitting end to receiving end is researched in detail. The mathematical mode including signal transmission, summing, receiving and recovering are established respectively. One of the main sources of Bit Error Rate (BER) of OCDMA system based on FBGs is the unevenness of signal power spectrum, which leads to the chip powers unequal with each other. The Signal to Interfere Ratio (SIR) and BER performance of the system are studied and simulated at the case with uneven distribution of chips' powers.展开更多
Ancient villages in Lingnan serve as crucial carriers of Lingnan culture.Their abundant cultural symbols now face the dual task of inheritance and innovation in the digital era.Drawing on Stuart Hall’s encoding/decod...Ancient villages in Lingnan serve as crucial carriers of Lingnan culture.Their abundant cultural symbols now face the dual task of inheritance and innovation in the digital era.Drawing on Stuart Hall’s encoding/decoding theory,this study explores how representative cultural symbols of Lingnan’s ancient villages are digitally translated and disseminated.By analyzing specific cases,it elucidates the logic of audience interaction and consumption during the decoding of these digital cultural symbols.This study aims to offer valuable insights for revitalizing ancient village culture and informing its sustainable industrial development.展开更多
With the growing adoption of automated guided vehicles(AGVs)in various industries,the integrated production and transportation scheduling problem(IPTSP)has emerged as a critical research focus.The IPTSP is classified ...With the growing adoption of automated guided vehicles(AGVs)in various industries,the integrated production and transportation scheduling problem(IPTSP)has emerged as a critical research focus.The IPTSP is classified as a strongly NP-hard problem due to the simultaneous scheduling of two resources:machines and transportation equipment.Meta-heuristic algorithms are one of the most popular and effective approaches to solving this problem.However,their effectiveness heavily depends on the choice of solution representation,which influences both the algorithm’s search space and convergence speed.This paper reviews the existing encoding and decoding methods and proposes a novel active decoding approach.Based on different combinations of encoding and decoding methods,six solution representations are identified,among which the newly proposed representation offers a trade-off between the search space and the algorithm’s efficiency.Specifically,four scenarios of IPTSP under different assumptions are first analyzed.Next,the variations in the six solution representations across unused scenarios and different layouts,as well as their respective encoding spaces and qualities,are summarized.Subsequently,the search efficiency of the six solution representations is evaluated using a genetic algorithm to analyze their performance under different scenarios,layouts,time ratios,and number of AGVs.Finally,the advantages,disadvantages and applicable scenes for each solution representation are summarized based on the experimental results and analysis.These findings provide valuable insights for designing more efficient algorithms to address the IPTSP.展开更多
with the development of 5G,the future wireless communication network tends to be more and more intelligent.In the face of new service de-mands of communication in the future such as super-heterogeneous network,multipl...with the development of 5G,the future wireless communication network tends to be more and more intelligent.In the face of new service de-mands of communication in the future such as super-heterogeneous network,multiple communication sce-narios,large number of antenna elements and large bandwidth,new theories and technologies of intelli-gent communication have been widely studied,among which Deep Learning(DL)is a powerful technology in artificial intelligence(AI).It can be trained to con-tinuously learn to update the optimal parameters.This paper reviews the latest research progress of DL in in-telligent communication,and emphatically introduces five scenarios including Cognitive Radio(CR),Edge Computing(EC),Channel Measurement(CM),End to end Encoder/Decoder(EED)and Visible Light Com-munication(VLC).The prospect and challenges of further research and development in the future are also discussed.展开更多
This paper focuses on a pattern design method for a 3D triangular garment surface. Firstly, some definitions of 3D style lines are proposed for designing the boundaries of patterns as drawing straight lines or splines...This paper focuses on a pattern design method for a 3D triangular garment surface. Firstly, some definitions of 3D style lines are proposed for designing the boundaries of patterns as drawing straight lines or splines on the triangular surface. Additionally some commonly used style lines are automatically generated to enhance design efficiency. Secondly, after style lines are preprocessed, a searching method is presented for quickly obtaining the boundaries and patches of a pattern on the 3D trian- gular surface. Finally a new pattern design reuse method is introduced by encoding/decoding the style line information. After style lines are encoded, the pattern design information can be saved in a pattern template and when decoding this template on a new garment surface, it automates the pattern generation for made-to-measure apparel products.展开更多
Fountain codes are considered to be a promising coding technique in underwater acoustic communication（UAC） which is challenged with the unique propagation features of the underwater acoustic channel and the harsh ma...Fountain codes are considered to be a promising coding technique in underwater acoustic communication（UAC） which is challenged with the unique propagation features of the underwater acoustic channel and the harsh marine environment. And Luby transform（LT） codes are the first codes fully realizing the digital fountain concept. However, in conventional LT encoding/decoding algorithms, due to the imperfect coverage（IC） of input symbols and short cycles in the generator matrix, stopping sets would occur and terminate the decoding. Thus, the recovery probability is reduced,high coding overhead is required and decoding delay is increased.These issues would be disadvantages while applying LT codes in underwater acoustic communication. Aimed at solving those issues, novel encoding/decoding algorithms are proposed. First,a doping and non-uniform selecting（DNS） encoding algorithm is proposed to solve the IC and the generation of short cycles problems. And this can reduce the probability of stopping sets occur during decoding. Second, a hybrid on the fly Gaussian elimination and belief propagation（OFG-BP） decoding algorithm is designed to reduce the decoding delay and efficiently utilize the information of stopping sets. Comparisons via Monte Carlo simulation confirm that the proposed schemes could achieve better overall decoding performances in comparison with conventional schemes.展开更多
We report the LPG pair device that can be used as a pulse duplicator or an OCDMA encoder/decoder. Due to the ring core region of dispersion compensating fiber (DCF), we can shorten the device length by a third and obt...We report the LPG pair device that can be used as a pulse duplicator or an OCDMA encoder/decoder. Due to the ring core region of dispersion compensating fiber (DCF), we can shorten the device length by a third and obtain surrounding insensitive LPG devices.展开更多
A new encoder/decoder scheme of OCDMA based on waveguide is proposed in this paper. The principle as well as the structure of waveguide encoder/decoder is given. It can be seen that all optical OCDMA encoder/...A new encoder/decoder scheme of OCDMA based on waveguide is proposed in this paper. The principle as well as the structure of waveguide encoder/decoder is given. It can be seen that all optical OCDMA encoder/decoder can be realized by the proposed scheme of the waveguide encoder/decoder. It can also make the OCDMA encoder/decoder integrated easily and the access controlled easily. The system based on this scheme can work under the entirely asynchronous condition.展开更多
Many monographs point out that differential encoding and decoding is necessary for ef- fectual information transmission against phase ambiguity while seldom discuss the reason why phase ambiguity will emerge inevitabl...Many monographs point out that differential encoding and decoding is necessary for ef- fectual information transmission against phase ambiguity while seldom discuss the reason why phase ambiguity will emerge inevitably.Available algorithms are specially designed for certain modulation scheme;these algorithms cannot satisfy the requirement of soft-defined radio,which perhaps demands a uniform algorithm for different modulations.This paper proposes a new opinion on phase ambiguity from the view of probability.This opinion believes that modulating symbol sequence can affect,at optimum sampling epoch,the modulated waveform as oscillating carrier has done,and so the stochastic sequence leads to phase ambiguity.Based on a general signal model,this paper also puts forward a novel universal algorithm,which is suitable for different signals,even some new ones,by configuring several parameters.展开更多
In this paper, we apply the perfect difference codes in wireless infrared systems considering the diffuse indoor optical wireless configuration. The bit error rate performance of the uplink wireless infrared system us...In this paper, we apply the perfect difference codes in wireless infrared systems considering the diffuse indoor optical wireless configuration. The bit error rate performance of the uplink wireless infrared system using Gaussian approximations is analyzed taking into account the effects of multiple-access interference, the ambient light noise, and the dark current. The proposed system also uses the compact encoder and decoder architecture resulting in a low cost system.展开更多
A novel lower-complexity construction scheme of quasi-cyclic low-density parity-check(QC-LDPC) codes for optical transmission systems is proposed based on the structure of the parity-check matrix for the Richardson-Ur...A novel lower-complexity construction scheme of quasi-cyclic low-density parity-check(QC-LDPC) codes for optical transmission systems is proposed based on the structure of the parity-check matrix for the Richardson-Urbanke(RU) algorithm. Furthermore, a novel irregular QC-LDPC(4 288, 4 020) code with high code-rate of 0.937 is constructed by this novel construction scheme. The simulation analyses show that the net coding gain(NCG) of the novel irregular QC-LDPC(4 288,4 020) code is respectively 2.08 d B, 1.25 d B and 0.29 d B more than those of the classic RS(255, 239) code, the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code at the bit error rate(BER) of 10^(-6). The irregular QC-LDPC(4 288, 4 020) code has the lower encoding/decoding complexity compared with the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code. The proposed novel QC-LDPC(4 288, 4 020) code can be more suitable for the increasing development requirements of high-speed optical transmission systems.展开更多
A family of array codes with a maximum distance separable（MDS） property, named L codes, is proposed. The greatest strength of L codes is that the number of rows（columns） in a disk array does not be restricted by t...A family of array codes with a maximum distance separable（MDS） property, named L codes, is proposed. The greatest strength of L codes is that the number of rows（columns） in a disk array does not be restricted by the prime number, and more disks can be dynamically appended in a running storage system. L codes can tolerate at least two disk erasures and some sector loss simultaneously, and can tolerate multiple disk erasures（greater than or equal to three） under a certain condition. Because only XOR operations are needed in the process of encoding and decoding, L codes have very high computing efficiency which is roughly equivalent to X codes. Analysis shows that L codes are particularly suitable for large-scale storage systems.展开更多
As the development of technology and education,translation has become a special field with an increasing importance in the society.As a consequence,monolingual and bilingual dictionaries have more vital functions duri...As the development of technology and education,translation has become a special field with an increasing importance in the society.As a consequence,monolingual and bilingual dictionaries have more vital functions during the process of translating.Due to the limitation of this paper,the author will only discuss the process of translating.The view taken here,representing the thesis of this essay,is by analyzing the process of how the students of English major use bilingual dictionaries during their translating process from English to Chinese,to get data and way on their translating process and the elements that could contribute to suitable bilingual dictionaries for the students.展开更多
Surrogate modeling techniques have become indispensable in accelerating the discovery and optimization of high-entropy alloys(HEAs),especially when integrating computational predictions with sparse experimental observ...Surrogate modeling techniques have become indispensable in accelerating the discovery and optimization of high-entropy alloys(HEAs),especially when integrating computational predictions with sparse experimental observations.This study systematically evaluates the training and testing performance of four prominent surrogate models—conventional Gaussian processes(cGP),Deep Gaussian processes(DGP),encoder-decoder neural networks for multi-output regression and eXtreme Gradient Boosting(XGBoost)—applied to a hybrid dataset of experimental and computational properties of the 8-component HEA system Al-Co-Cr-Cu-Fe-Mn-Ni-V.We specifically assess their capabilities in predicting correlated material properties,including yield strength,hardness,modulus,ultimate tensile strength,elongation,and average hardness under dynamic/quasi-static conditions,alongside auxiliary computational properties.The comparison highlights the strengths of hierarchical deep modeling approaches in handling heteroscedastic,heterotopic,and incomplete data commonly encountered in materials science.Our findings illustrate that combined surrogate models such as DGPs infused with machine-learned priors outperformother surrogates by effectively capturing inter-property correlations and by assimilating prior knowledge.This enhanced predictive accuracy positions the combined surrogate models as powerful tools for robust and dataefficient materials design.展开更多
Computational optics introduces computation into optics and consequently helps overcome traditional optical limitations such as low sensing dimension,low light throughput,low resolution,and so on.The combination of op...Computational optics introduces computation into optics and consequently helps overcome traditional optical limitations such as low sensing dimension,low light throughput,low resolution,and so on.The combination of optical encoding and computational decoding offers enhanced imaging and sensing capabilities with diverse applications in biomedicine,astronomy,agriculture,etc.With the great advance of artificial intelligence in the last decade,deep learning has further boosted computational optics with higher precision and efficiency.Recently,there developed an end-to-end joint optimization technique that digitally twins optical encoding to neural network layers,and then facilitates simultaneous optimization with the decoding process.This framework offers effective performance enhancement over conventional techniques.However,the reverse physical twinning from optimized encoding parameters to practical modulation elements faces a serious challenge,due to the discrepant gap in such as bit depth,numerical range,and stability.In this regard,this review explores various optical modulation elements across spatial,phase,and spectral dimensions in the digital twin model for joint encoding-decoding optimization.Our analysis offers constructive guidance for finding the most appropriate modulation element in diverse imaging and sensing tasks concerning various requirements of precision,speed,and robustness.The review may help tackle the above twinning challenge and pave the way for next-generation computational optics.展开更多
In this study,we propose and demonstrate an all-fiber orbital-angular-momentum(OAM)mode encoding system,where through helical fiber gratings(HFGs),binary symbols are encoded to or decoded from two OAM modes with topol...In this study,we propose and demonstrate an all-fiber orbital-angular-momentum(OAM)mode encoding system,where through helical fiber gratings(HFGs),binary symbols are encoded to or decoded from two OAM modes with topological charges(TCs)of-1 and+1,respectively.We experimentally validate that the OAM mode generated by a clockwise-helix HFG(cHFG)can be converted back into fundamental mode by using an HFG with a helix orientation opposite to that of the cHFG,i.e.,ccHFG.Benefited from utilization of the HFGs,the proposed OAM mode encoding system has a low cost,low insertion loss,high mode conversion efficiency,and polarization independence.To the best of our knowledge,this is the first demonstration of the HFGs-based all-fiber OAM mode encoding/decoding scheme,which may find potential applications in optical communication and quantum communication as well.展开更多
Identifying crack and predicting crack propagation are critical processes for the risk assessment of engineering structures.Most traditional approaches to crack modeling are faced with issues of high computational cos...Identifying crack and predicting crack propagation are critical processes for the risk assessment of engineering structures.Most traditional approaches to crack modeling are faced with issues of high computational costs and excessive computing time.To address this issue,we explore the potential of deep learning(DL)to increase the efficiency of crack detection and forecasting crack growth.However,there is no single algorithm that can fit all data sets well or can apply in all cases since specific tasks vary.In the paper,we present DL models for identifying cracks,especially on concrete surface images,and for predicting crack propagation.Firstly,SegNet and U-Net networks are used to identify concrete cracks.Stochastic gradient descent(SGD)and adaptive moment estimation(Adam)algorithms are applied to minimize loss function during iterations.Secondly,time series algorithms including gated recurrent unit(GRU)and long short-term memory(LSTM)are used to predict crack propagation.The experimental findings indicate that the U-Net is more robust and efficient than the SegNet for identifying crack segmentation and achieves the most outstanding results.For evaluation of crack propagation,GRU and LSTM are used as DL models and results show good agreement with the experimental data.展开更多
Bundle recommendation offers users more holistic insights by recommending multiple compatible items at once.However,the intricate correlations between items,varied user preferences,and the pronounced data sparsity in ...Bundle recommendation offers users more holistic insights by recommending multiple compatible items at once.However,the intricate correlations between items,varied user preferences,and the pronounced data sparsity in combinations present significant challenges for bundle recommendation algorithms.Furthermore,current bundle recommendation methods fail to identify mismatched items within a given set,a process termed as‘‘outlier item detection’’.These outlier items are those with the weakest correlations within a bundle.Identifying them can aid users in refining their item combinations.While the correlation among items can predict the detection of such outliers,the adaptability of combinations might not be adequately responsive to shifts in individual items during the learning phase.This limitation can hinder the algorithm’s performance.To tackle these challenges,we introduce an encoder–decoder architecture tailored for outlier item detection.The encoder learns potential item correlations through a self-attention mechanism.Concurrently,the decoder garners efficient inference frameworks by directly assessing item anomalies.We have validated the efficacy and efficiency of our proposed algorithm using real-world datasets.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 6226070954Jiangxi Provincial Key R&D Programme under Grant 20244BBG73002.
文摘Rail surface damage is a critical component of high-speed railway infrastructure,directly affecting train operational stability and safety.Existing methods face limitations in accuracy and speed for small-sample,multi-category,and multi-scale target segmentation tasks.To address these challenges,this paper proposes Pyramid-MixNet,an intelligent segmentation model for high-speed rail surface damage,leveraging dataset construction and expansion alongside a feature pyramid-based encoder-decoder network with multi-attention mechanisms.The encoding net-work integrates Spatial Reduction Masked Multi-Head Attention(SRMMHA)to enhance global feature extraction while reducing trainable parameters.The decoding network incorporates Mix-Attention(MA),enabling multi-scale structural understanding and cross-scale token group correlation learning.Experimental results demonstrate that the proposed method achieves 62.17%average segmentation accuracy,80.28%Damage Dice Coefficient,and 56.83 FPS,meeting real-time detection requirements.The model’s high accuracy and scene adaptability significantly improve the detection of small-scale and complex multi-scale rail damage,offering practical value for real-time monitoring in high-speed railway maintenance systems.
基金Supported by the Natural Science Research Foundation of Jiangsu Higher-Learning Insti-tution (No.04jkb510057).
文摘The encoding/decoding scheme based on Fiber Bragg Grating (FBG) for Optical Code Division Multiple Access (OCDMA) system is analyzed and the whole process from transmitting end to receiving end is researched in detail. The mathematical mode including signal transmission, summing, receiving and recovering are established respectively. One of the main sources of Bit Error Rate (BER) of OCDMA system based on FBGs is the unevenness of signal power spectrum, which leads to the chip powers unequal with each other. The Signal to Interfere Ratio (SIR) and BER performance of the system are studied and simulated at the case with uneven distribution of chips' powers.
基金2025 Institutional-Level Scientific Research Project of South China Business College,Guangdong University of Foreign Studies,“Digital Dissemination and Consumer Behaviour Research:Cultural Symbols of Lingnan Heritage Villages”(Project No.:25-005C)。
文摘Ancient villages in Lingnan serve as crucial carriers of Lingnan culture.Their abundant cultural symbols now face the dual task of inheritance and innovation in the digital era.Drawing on Stuart Hall’s encoding/decoding theory,this study explores how representative cultural symbols of Lingnan’s ancient villages are digitally translated and disseminated.By analyzing specific cases,it elucidates the logic of audience interaction and consumption during the decoding of these digital cultural symbols.This study aims to offer valuable insights for revitalizing ancient village culture and informing its sustainable industrial development.
基金Supported by National Key R&D Program of China(Grant No.2022YFB3302700)National Natural Science Foundation of China(Grant No.U21B2029)Fundamental Research Funds for the Central Universities(Grant No.2024BRA004).
文摘With the growing adoption of automated guided vehicles(AGVs)in various industries,the integrated production and transportation scheduling problem(IPTSP)has emerged as a critical research focus.The IPTSP is classified as a strongly NP-hard problem due to the simultaneous scheduling of two resources:machines and transportation equipment.Meta-heuristic algorithms are one of the most popular and effective approaches to solving this problem.However,their effectiveness heavily depends on the choice of solution representation,which influences both the algorithm’s search space and convergence speed.This paper reviews the existing encoding and decoding methods and proposes a novel active decoding approach.Based on different combinations of encoding and decoding methods,six solution representations are identified,among which the newly proposed representation offers a trade-off between the search space and the algorithm’s efficiency.Specifically,four scenarios of IPTSP under different assumptions are first analyzed.Next,the variations in the six solution representations across unused scenarios and different layouts,as well as their respective encoding spaces and qualities,are summarized.Subsequently,the search efficiency of the six solution representations is evaluated using a genetic algorithm to analyze their performance under different scenarios,layouts,time ratios,and number of AGVs.Finally,the advantages,disadvantages and applicable scenes for each solution representation are summarized based on the experimental results and analysis.These findings provide valuable insights for designing more efficient algorithms to address the IPTSP.
基金the National Nat-ural Science Foundation of China under Grant No.62061039Postgraduate Innovation Project of Ningxia University No.JIP20210076Key project of Ningxia Natural Science Foundation No.2020AAC02006.
文摘with the development of 5G,the future wireless communication network tends to be more and more intelligent.In the face of new service de-mands of communication in the future such as super-heterogeneous network,multiple communication sce-narios,large number of antenna elements and large bandwidth,new theories and technologies of intelli-gent communication have been widely studied,among which Deep Learning(DL)is a powerful technology in artificial intelligence(AI).It can be trained to con-tinuously learn to update the optimal parameters.This paper reviews the latest research progress of DL in in-telligent communication,and emphatically introduces five scenarios including Cognitive Radio(CR),Edge Computing(EC),Channel Measurement(CM),End to end Encoder/Decoder(EED)and Visible Light Com-munication(VLC).The prospect and challenges of further research and development in the future are also discussed.
基金Project supported by the National Natural Science Foundation of China (No. 60473129)the Ph.D Programs Foundation of the Ministry of Education of China (No. 20060335118)
文摘This paper focuses on a pattern design method for a 3D triangular garment surface. Firstly, some definitions of 3D style lines are proposed for designing the boundaries of patterns as drawing straight lines or splines on the triangular surface. Additionally some commonly used style lines are automatically generated to enhance design efficiency. Secondly, after style lines are preprocessed, a searching method is presented for quickly obtaining the boundaries and patches of a pattern on the 3D trian- gular surface. Finally a new pattern design reuse method is introduced by encoding/decoding the style line information. After style lines are encoded, the pattern design information can be saved in a pattern template and when decoding this template on a new garment surface, it automates the pattern generation for made-to-measure apparel products.
基金supported by the National Natural Science Foundation of China(61371099)the Fundamental Research Funds for the Central Universities of China(HEUCF150812/150810)
文摘Fountain codes are considered to be a promising coding technique in underwater acoustic communication（UAC） which is challenged with the unique propagation features of the underwater acoustic channel and the harsh marine environment. And Luby transform（LT） codes are the first codes fully realizing the digital fountain concept. However, in conventional LT encoding/decoding algorithms, due to the imperfect coverage（IC） of input symbols and short cycles in the generator matrix, stopping sets would occur and terminate the decoding. Thus, the recovery probability is reduced,high coding overhead is required and decoding delay is increased.These issues would be disadvantages while applying LT codes in underwater acoustic communication. Aimed at solving those issues, novel encoding/decoding algorithms are proposed. First,a doping and non-uniform selecting（DNS） encoding algorithm is proposed to solve the IC and the generation of short cycles problems. And this can reduce the probability of stopping sets occur during decoding. Second, a hybrid on the fly Gaussian elimination and belief propagation（OFG-BP） decoding algorithm is designed to reduce the decoding delay and efficiently utilize the information of stopping sets. Comparisons via Monte Carlo simulation confirm that the proposed schemes could achieve better overall decoding performances in comparison with conventional schemes.
文摘We report the LPG pair device that can be used as a pulse duplicator or an OCDMA encoder/decoder. Due to the ring core region of dispersion compensating fiber (DCF), we can shorten the device length by a third and obtain surrounding insensitive LPG devices.
文摘A new encoder/decoder scheme of OCDMA based on waveguide is proposed in this paper. The principle as well as the structure of waveguide encoder/decoder is given. It can be seen that all optical OCDMA encoder/decoder can be realized by the proposed scheme of the waveguide encoder/decoder. It can also make the OCDMA encoder/decoder integrated easily and the access controlled easily. The system based on this scheme can work under the entirely asynchronous condition.
基金Supported by Henan Prominent Talents Innovation Foundation (No.0421000100).
文摘Many monographs point out that differential encoding and decoding is necessary for ef- fectual information transmission against phase ambiguity while seldom discuss the reason why phase ambiguity will emerge inevitably.Available algorithms are specially designed for certain modulation scheme;these algorithms cannot satisfy the requirement of soft-defined radio,which perhaps demands a uniform algorithm for different modulations.This paper proposes a new opinion on phase ambiguity from the view of probability.This opinion believes that modulating symbol sequence can affect,at optimum sampling epoch,the modulated waveform as oscillating carrier has done,and so the stochastic sequence leads to phase ambiguity.Based on a general signal model,this paper also puts forward a novel universal algorithm,which is suitable for different signals,even some new ones,by configuring several parameters.
文摘In this paper, we apply the perfect difference codes in wireless infrared systems considering the diffuse indoor optical wireless configuration. The bit error rate performance of the uplink wireless infrared system using Gaussian approximations is analyzed taking into account the effects of multiple-access interference, the ambient light noise, and the dark current. The proposed system also uses the compact encoder and decoder architecture resulting in a low cost system.
基金supported by the National Natural Science Foundation of China(Nos.61472464 and 61471075)the Program for Innovation Team Building at Institutions of Higher Education in Chongqing(No.J2013-46)+1 种基金the Natural Science Foundation of Chongqing Science and Technology Commission(Nos.cstc2015jcyjA 0554 and cstc2013jcyjA 40017)the Program for Postgraduate Science Research and Innovation of Chongqing University of Posts and Telecommunications(Chongqing Municipal Education Commission)(No.CYS14144)
文摘A novel lower-complexity construction scheme of quasi-cyclic low-density parity-check(QC-LDPC) codes for optical transmission systems is proposed based on the structure of the parity-check matrix for the Richardson-Urbanke(RU) algorithm. Furthermore, a novel irregular QC-LDPC(4 288, 4 020) code with high code-rate of 0.937 is constructed by this novel construction scheme. The simulation analyses show that the net coding gain(NCG) of the novel irregular QC-LDPC(4 288,4 020) code is respectively 2.08 d B, 1.25 d B and 0.29 d B more than those of the classic RS(255, 239) code, the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code at the bit error rate(BER) of 10^(-6). The irregular QC-LDPC(4 288, 4 020) code has the lower encoding/decoding complexity compared with the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code. The proposed novel QC-LDPC(4 288, 4 020) code can be more suitable for the increasing development requirements of high-speed optical transmission systems.
基金supported by the National Natural Science Foundation of China under Grant No.61202250
文摘A family of array codes with a maximum distance separable（MDS） property, named L codes, is proposed. The greatest strength of L codes is that the number of rows（columns） in a disk array does not be restricted by the prime number, and more disks can be dynamically appended in a running storage system. L codes can tolerate at least two disk erasures and some sector loss simultaneously, and can tolerate multiple disk erasures（greater than or equal to three） under a certain condition. Because only XOR operations are needed in the process of encoding and decoding, L codes have very high computing efficiency which is roughly equivalent to X codes. Analysis shows that L codes are particularly suitable for large-scale storage systems.
文摘As the development of technology and education,translation has become a special field with an increasing importance in the society.As a consequence,monolingual and bilingual dictionaries have more vital functions during the process of translating.Due to the limitation of this paper,the author will only discuss the process of translating.The view taken here,representing the thesis of this essay,is by analyzing the process of how the students of English major use bilingual dictionaries during their translating process from English to Chinese,to get data and way on their translating process and the elements that could contribute to suitable bilingual dictionaries for the students.
基金supported by the Texas A&M University System National Laboratories Office of the Texas A&M University System and Los Alamos National Laboratory as part of the Joint Research Collaboration Program. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Los Alamos National Laboratory or The Texas A&M University Systemsupport from the U.S. Department of Energy (DOE) ARPA-E CHADWICK Program through Project DE‐AR0001988JJ acknowledges support from the Los Alamos National Laboratory Laboratory (LANL) Laboratory Directed Research and Development Program under project number 20220815PRD4. LANL is operated by Triad National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy (Contract No. 89233218CNA000001). Original data were generated within the BIRDSHOT Center (https://birdshot.tamu.edu), supported by the Army Research Laboratory under Cooperative Agreement (CA) NumberW911NF-22-2-0106 (MM, DK, DA, VA and RA acknowledge partial support from this CA). NF acknowledges support from AFRL through a subcontract with ARCTOS, TOPS VI (165852-19F5830-19-02-C1). Calculations were carried out at Texas A&M High-Performance Research Computing (HPRC).
文摘Surrogate modeling techniques have become indispensable in accelerating the discovery and optimization of high-entropy alloys(HEAs),especially when integrating computational predictions with sparse experimental observations.This study systematically evaluates the training and testing performance of four prominent surrogate models—conventional Gaussian processes(cGP),Deep Gaussian processes(DGP),encoder-decoder neural networks for multi-output regression and eXtreme Gradient Boosting(XGBoost)—applied to a hybrid dataset of experimental and computational properties of the 8-component HEA system Al-Co-Cr-Cu-Fe-Mn-Ni-V.We specifically assess their capabilities in predicting correlated material properties,including yield strength,hardness,modulus,ultimate tensile strength,elongation,and average hardness under dynamic/quasi-static conditions,alongside auxiliary computational properties.The comparison highlights the strengths of hierarchical deep modeling approaches in handling heteroscedastic,heterotopic,and incomplete data commonly encountered in materials science.Our findings illustrate that combined surrogate models such as DGPs infused with machine-learned priors outperformother surrogates by effectively capturing inter-property correlations and by assimilating prior knowledge.This enhanced predictive accuracy positions the combined surrogate models as powerful tools for robust and dataefficient materials design.
基金supported by the National Natural Science Foundation of China(Nos.62131003,62322502,62088101)the Guangdong Province Key Laboratory of Intelligent Detection in Complex Environment of Aerospace,Land and Sea(No.2022KSYS016).
文摘Computational optics introduces computation into optics and consequently helps overcome traditional optical limitations such as low sensing dimension,low light throughput,low resolution,and so on.The combination of optical encoding and computational decoding offers enhanced imaging and sensing capabilities with diverse applications in biomedicine,astronomy,agriculture,etc.With the great advance of artificial intelligence in the last decade,deep learning has further boosted computational optics with higher precision and efficiency.Recently,there developed an end-to-end joint optimization technique that digitally twins optical encoding to neural network layers,and then facilitates simultaneous optimization with the decoding process.This framework offers effective performance enhancement over conventional techniques.However,the reverse physical twinning from optimized encoding parameters to practical modulation elements faces a serious challenge,due to the discrepant gap in such as bit depth,numerical range,and stability.In this regard,this review explores various optical modulation elements across spatial,phase,and spectral dimensions in the digital twin model for joint encoding-decoding optimization.Our analysis offers constructive guidance for finding the most appropriate modulation element in diverse imaging and sensing tasks concerning various requirements of precision,speed,and robustness.The review may help tackle the above twinning challenge and pave the way for next-generation computational optics.
基金National Key Research and Development Program of China(2023YFB2804900)National Natural Science Foundation of China(62375134)+2 种基金Japan Society for the Promotion of Science(JP24K21609,JP23K22816)Amano Institute of TechnologyNatural Science Research of Jiangsu Higher Education Institutions of China(22KJB510030)。
文摘In this study,we propose and demonstrate an all-fiber orbital-angular-momentum(OAM)mode encoding system,where through helical fiber gratings(HFGs),binary symbols are encoded to or decoded from two OAM modes with topological charges(TCs)of-1 and+1,respectively.We experimentally validate that the OAM mode generated by a clockwise-helix HFG(cHFG)can be converted back into fundamental mode by using an HFG with a helix orientation opposite to that of the cHFG,i.e.,ccHFG.Benefited from utilization of the HFGs,the proposed OAM mode encoding system has a low cost,low insertion loss,high mode conversion efficiency,and polarization independence.To the best of our knowledge,this is the first demonstration of the HFGs-based all-fiber OAM mode encoding/decoding scheme,which may find potential applications in optical communication and quantum communication as well.
基金The first author would like to thank European Commission H2020-MSCA-RISE BESTOFRAC project for research funding.
文摘Identifying crack and predicting crack propagation are critical processes for the risk assessment of engineering structures.Most traditional approaches to crack modeling are faced with issues of high computational costs and excessive computing time.To address this issue,we explore the potential of deep learning(DL)to increase the efficiency of crack detection and forecasting crack growth.However,there is no single algorithm that can fit all data sets well or can apply in all cases since specific tasks vary.In the paper,we present DL models for identifying cracks,especially on concrete surface images,and for predicting crack propagation.Firstly,SegNet and U-Net networks are used to identify concrete cracks.Stochastic gradient descent(SGD)and adaptive moment estimation(Adam)algorithms are applied to minimize loss function during iterations.Secondly,time series algorithms including gated recurrent unit(GRU)and long short-term memory(LSTM)are used to predict crack propagation.The experimental findings indicate that the U-Net is more robust and efficient than the SegNet for identifying crack segmentation and achieves the most outstanding results.For evaluation of crack propagation,GRU and LSTM are used as DL models and results show good agreement with the experimental data.
基金supported in part by the Guangxi Key Laboratory of Trusted Software,China(KX202037)the Project of Guangxi Science and Technology,China(GuiKeAD 20297054)the Guangxi Natural Science Foundation Project,China(2020GXNSFBA297108)。
文摘Bundle recommendation offers users more holistic insights by recommending multiple compatible items at once.However,the intricate correlations between items,varied user preferences,and the pronounced data sparsity in combinations present significant challenges for bundle recommendation algorithms.Furthermore,current bundle recommendation methods fail to identify mismatched items within a given set,a process termed as‘‘outlier item detection’’.These outlier items are those with the weakest correlations within a bundle.Identifying them can aid users in refining their item combinations.While the correlation among items can predict the detection of such outliers,the adaptability of combinations might not be adequately responsive to shifts in individual items during the learning phase.This limitation can hinder the algorithm’s performance.To tackle these challenges,we introduce an encoder–decoder architecture tailored for outlier item detection.The encoder learns potential item correlations through a self-attention mechanism.Concurrently,the decoder garners efficient inference frameworks by directly assessing item anomalies.We have validated the efficacy and efficiency of our proposed algorithm using real-world datasets.
