This research intends to find out the optimal mechanical properties of AISI 4130 steel welded by the GTAW process. Six test plates were joined by two types of filler wire with similar chemical composition to the base ...This research intends to find out the optimal mechanical properties of AISI 4130 steel welded by the GTAW process. Six test plates were joined by two types of filler wire with similar chemical composition to the base metal, and with lower carbon content and slightly higher alloy elements content compared to the first one. Test plates then exerted three different pre-heat and post-heat treatments on both groups. The three types of heat treatments were alternatively without pre-heat and post-heat, with pre-heat only, and finally with pre-heat and post-heat. Tensile, side bends and impact tests (for weld zone and HAZ) have been conducted. Results show that using low-carbon filler wire along with pre- and post-heat resulted in outstanding mechanical properties.展开更多
A single-channel electroencephalography(EEG)device,despite being widely accepted due to convenience,ease of deployment and suitability for use in complex environments,typically poses a great challenge for reactive bra...A single-channel electroencephalography(EEG)device,despite being widely accepted due to convenience,ease of deployment and suitability for use in complex environments,typically poses a great challenge for reactive brain-computer interface(BCI)applications particularly when a continuous command from users is desired to run a motorized actuator with different speed profiles.In this study,a combination of an inconspicuous visual stimulus and voluntary eyeblinks along with a machine learning-based decoder is considered as a new reactive BCI paradigm to increase the degree of freedom and minimize mismatches between the intended dynamic command and transmitted control signal.The proposed decoder is constructed based on Gaussian Process model(GPM)which is a nonparametric Bayesian approach that has the advantages of being able to operate on small datasets and providing measurements of uncertainty on predictions.To evaluate the effectiveness of the proposed method,the GPM is compared against other competitive techniques which include k-Nearest Neighbors,linear discriminant analysis,support vector machine,ensemble learning and neural network.Results demonstrate that a significant improvement can be achieved via the GPM approach with average accuracy reaching over 96%and mean absolute error of no greater than 0.8 cm/s.In addition,the analysis reveals that while the performances of other existing methods deteriorate with a certain type of stimulus due to signal drifts resulting from the voluntary eyeblinks,the proposed GPM exhibits consistent performance across all stimuli considered,thereby manifesting its generalization capability and making it a more suitable option for dynamic commands with a single-channel EEG-controlled actuator.展开更多
农业测控系统的用户交互性存在改进空间,随着自然语言语义处理技术的不断进步,提升农业测控领域中复杂的控制和查询操作的用户友好性变得至关重要,这有助于降低用户的操作成本。本文提出了一种面向农业测控领域的自然语言接口(agricultu...农业测控系统的用户交互性存在改进空间,随着自然语言语义处理技术的不断进步,提升农业测控领域中复杂的控制和查询操作的用户友好性变得至关重要,这有助于降低用户的操作成本。本文提出了一种面向农业测控领域的自然语言接口(agricultural measurement and control natural language interface,AMC-NLI),旨在改进农业测控平台的用户体验。通过BERT-BiLSTM-ATT-CRF-OPO(bidirectional encoder representations from transformers-bi-directional long shortterm memory-attention-conditional random field)的语义解析模型,识别并提取农业指令中的实体,并进行操作-地点-对象三元组语句(operate-place-object,OPO)的槽填充。使得用户的自然语言输入能够被转化为结构化的三元组语句,实现用户输入的指令转换为相应的参数,并通过物联网网关发送到相应的设备。试验结果表明在AMC-NLI农业测控指令交互方面,该模型表现出色,准确率,精确率、召回率,F值和平均最大响应时间分别达到了91.63%、92.77%、92.48%、91.74%和2.45 s,为农业信息化管控提供了更为便捷的互动方式。展开更多
文摘This research intends to find out the optimal mechanical properties of AISI 4130 steel welded by the GTAW process. Six test plates were joined by two types of filler wire with similar chemical composition to the base metal, and with lower carbon content and slightly higher alloy elements content compared to the first one. Test plates then exerted three different pre-heat and post-heat treatments on both groups. The three types of heat treatments were alternatively without pre-heat and post-heat, with pre-heat only, and finally with pre-heat and post-heat. Tensile, side bends and impact tests (for weld zone and HAZ) have been conducted. Results show that using low-carbon filler wire along with pre- and post-heat resulted in outstanding mechanical properties.
基金This work was supported by the Ministry of Higher Education Malaysia for Fundamental Research Grant Scheme with Project Code:FRGS/1/2021/TK0/USM/02/18.
文摘A single-channel electroencephalography(EEG)device,despite being widely accepted due to convenience,ease of deployment and suitability for use in complex environments,typically poses a great challenge for reactive brain-computer interface(BCI)applications particularly when a continuous command from users is desired to run a motorized actuator with different speed profiles.In this study,a combination of an inconspicuous visual stimulus and voluntary eyeblinks along with a machine learning-based decoder is considered as a new reactive BCI paradigm to increase the degree of freedom and minimize mismatches between the intended dynamic command and transmitted control signal.The proposed decoder is constructed based on Gaussian Process model(GPM)which is a nonparametric Bayesian approach that has the advantages of being able to operate on small datasets and providing measurements of uncertainty on predictions.To evaluate the effectiveness of the proposed method,the GPM is compared against other competitive techniques which include k-Nearest Neighbors,linear discriminant analysis,support vector machine,ensemble learning and neural network.Results demonstrate that a significant improvement can be achieved via the GPM approach with average accuracy reaching over 96%and mean absolute error of no greater than 0.8 cm/s.In addition,the analysis reveals that while the performances of other existing methods deteriorate with a certain type of stimulus due to signal drifts resulting from the voluntary eyeblinks,the proposed GPM exhibits consistent performance across all stimuli considered,thereby manifesting its generalization capability and making it a more suitable option for dynamic commands with a single-channel EEG-controlled actuator.
文摘农业测控系统的用户交互性存在改进空间,随着自然语言语义处理技术的不断进步,提升农业测控领域中复杂的控制和查询操作的用户友好性变得至关重要,这有助于降低用户的操作成本。本文提出了一种面向农业测控领域的自然语言接口(agricultural measurement and control natural language interface,AMC-NLI),旨在改进农业测控平台的用户体验。通过BERT-BiLSTM-ATT-CRF-OPO(bidirectional encoder representations from transformers-bi-directional long shortterm memory-attention-conditional random field)的语义解析模型,识别并提取农业指令中的实体,并进行操作-地点-对象三元组语句(operate-place-object,OPO)的槽填充。使得用户的自然语言输入能够被转化为结构化的三元组语句,实现用户输入的指令转换为相应的参数,并通过物联网网关发送到相应的设备。试验结果表明在AMC-NLI农业测控指令交互方面,该模型表现出色,准确率,精确率、召回率,F值和平均最大响应时间分别达到了91.63%、92.77%、92.48%、91.74%和2.45 s,为农业信息化管控提供了更为便捷的互动方式。
