load model established in a road traffic scene is difficult to adapt to the changes of the surrounding road environment during the actual Objective:At present,most research on driver mental load identification is base...load model established in a road traffic scene is difficult to adapt to the changes of the surrounding road environment during the actual Objective:At present,most research on driver mental load identification is based on a single driving scene.However,the driver mental driving process.We proposed a driver mental load identification model which adapts to urban road traffie scenarios.scene discrimination sub-model can quickly and accurately determine the road traffic scene.The driver load identification sub-model Methods:The model includes a driving scene discrimination sub-model and driver load identification sub-model,in which the driving sub-model.selects the best feature subset and the best model algorithm in the scene based on the judgement of the driving scene classification Results:The results show that the driving scene discrimination sub-model using five vehicle features as feature subsets has the best performance.The driver load identification sub-model based on the best feature subset reduces the feature noise,and the recognition tends to be consistent,and the support vector machine(5VM)algorithm is better than the K-nearest neighbors(KNN)algorithm.effect is better than the feature set using a single source signal and all data.The best recognition algorithm in different scenarios Conclusion:The proposed driver mental load identificution model can discriminate the driving scene quickly and accurately,and then identify the driver mental load.In this way,our model can be more suitable for actual driving and improve the effect of driver mental load identification.展开更多
互通式立交承担着不同方向交通流的流向转换功能,是道路交通网络的重要节点。目前高密度立交在城市道路网络中已愈发常见,高密度立交之间的间距比普通立交更小,车辆交织更为密集,驾驶人需要在更短的时间内进行分合流驾驶操作。为探究立...互通式立交承担着不同方向交通流的流向转换功能,是道路交通网络的重要节点。目前高密度立交在城市道路网络中已愈发常见,高密度立交之间的间距比普通立交更小,车辆交织更为密集,驾驶人需要在更短的时间内进行分合流驾驶操作。为探究立交间距对驾驶人精神负荷的影响与高密度立交出入口区段的驾驶人精神负荷统计特性,在重庆市内环快速路上选择了1段包含4座连续立交的路段作为实验对象,其中3座立交为高密度立交。通过车载仪器采集47名驾驶人在实车实验过程中的心电数据,对在高密度立交出入口区段与普通间距立交出入口区段的驾驶人心率变异性时域和频域指标进行差异性分析,得到了驾驶人在高密度立交与普通间距立交出入口区段的精神负荷分布特征。研究结果表明:驾驶人在经过普通间距立交出入口区段和高密度立交出入口区段时的心率变异性时域指标不存在显著性差异,频域指标心率变异性的低、高频功率的比值(ratio of low-frequency to high-frequency,LF/HF)存在显著性差异,频域指标LF/HF可作为评价驾驶人精神负荷在立交出入口区段的主要指标;驾驶人在经过高密度立交入口区段时,频域指标LF/HF比经过普通间距立交入口区段时显著增加,立交间距不足会增加驾驶人在立交入口区段的精神负荷;驾驶人在经过普通间距立交出口区段时的心率变异性频域指标LF/HF比经过高密度立交出口区段时显著增加,即驾驶人通过普通间距立交出口区段的精神负荷更大;对于高密度立交群,驾驶人在入口区段的精神负荷水平要略高于出口区段。展开更多
近年来,随着人工智能领域技术的不断发展,人机交互领域吸引了更多学者的关注。研究表明由脑电图(electroencephalogram,EEG)提取的特征功率谱密度对于脑力负荷的变化比较敏感,但由于其维数过高,容易造成数据灾难。局部线性嵌入(locally ...近年来,随着人工智能领域技术的不断发展,人机交互领域吸引了更多学者的关注。研究表明由脑电图(electroencephalogram,EEG)提取的特征功率谱密度对于脑力负荷的变化比较敏感,但由于其维数过高,容易造成数据灾难。局部线性嵌入(locally linear embedding,LLE)是常用的非线性降维算法,该算法弥补了传统线性降维算法无法发现数据中非线性结构关系的不足。由于不同数据集中样本分布的稀疏程度和扭曲程度不同,在使用LLE对不同数据集进行降维时的最佳邻域参数也不同。利用样本点之间的欧氏距离和测地距离的关系量化了数据集的扭曲程度,自适应邻域参数的局部线性嵌入算法(variable k-locally linear embedding,VK-LLE)动态地调整每一个数据集的最佳邻域参数,解决了样本分布扭曲程度不同对降维效果造成的干扰。实验结果表明,经过VK-LLE降维后的数据使用支持向量机(support vector machine,SVM)分类精度普遍高于经过传统LLE的降维后再使用SVM分类的精度,对复杂数据集有更强的适应能力。展开更多
要为明确高密度互通立交行驶环境下,主线车流量对出入口区段驾驶人精神负荷间的影响,在重庆市内环快速路高密度互通立交群进行自然驾驶实车试验,使用Physiolab生理检测仪连续采集驾驶人在行驶过程中的心电数据,用于统计各驾驶人的心率...要为明确高密度互通立交行驶环境下,主线车流量对出入口区段驾驶人精神负荷间的影响,在重庆市内环快速路高密度互通立交群进行自然驾驶实车试验,使用Physiolab生理检测仪连续采集驾驶人在行驶过程中的心电数据,用于统计各驾驶人的心率指标变化情况。本次试验基于主成分分析法选择心率变异率指标RMSSD(root mean square of successive differences)、LFnorm(low frequency norm)、HFnorm(high frequency norm)、LF(low frequency)/HF(high frequency)以及心率突变率指标HRMR(heat ratemutation rate)作为驾驶人精神负荷的评价指标,记为主成分F 1和主成分F 2,并建立评价模型。结果表明:驾驶人在小净距立交出入口区段行驶时,立交主线车流量的大小会影响驾驶人的精神负荷;当驾驶人驶入立交主线时,三次模型对入口段车流量与主成分F 2的拟合效果最好,呈开口向上的三次曲线,曲线谷值点出现在2级流量水平处,模型显著;当驾驶人驶出立交主线时,一次线性模型对出口段车流量与主成分F 1的拟合效果最好,模型显著。展开更多
BACKGROUND： It has been demonstrated that patients with functional dyspepsia have experiences social life stress events, and accompanied by psychological disorders, mainly manifested as depression and anxiety.Mental ...BACKGROUND： It has been demonstrated that patients with functional dyspepsia have experiences social life stress events, and accompanied by psychological disorders, mainly manifested as depression and anxiety.Mental factors can lead to excessive gastrointestinal consensual reaction, and result in different brain-gut axis disturbance, and then cause the gastrointestinal sensorimotor abnormality and endocrine changes.OBJECTIVE： To observe the effect of antidepressant treatment on the changes of water load and serum cortisol in patients with functional dyspepsia, and analyze the therapeutic mechanism.DESIGN： A comparative observation.SETTING： The First Affiliated Hospital o Zhengzhou University.PARTICIPANTS： Forty-five patients with functional dyspepsia accompanied by depression were selected from the Department of Gastroenterology, the First Affiliated Hospital of Zhengzhou University from July 2004 to July 2006, and they were 25 - 65 years of age, and their disease courses ranged 1 - 10 years. They were all accorded with the diagnostic standards for Rome Ⅱ functional dyspepsia functional dyspepsia. As the patients＇ will, they were divided into treatment group （n =30, 12 males and 18 females） and control group （n =15, 6 males and 9 females）, and there were no significant differences in the data between the two groups （P 〉 0.05）. The programs were discussed and agreed by the committee of medical ethics of the First Affiliated Hospital of Zhengzhou University. Informed contents were obtained from all the patients.METHODS： In the treatment group, the patients were treated with venlafaxine sustained release capsule （75 mg per day）, and those with sleep disorder were added by benzodiazepines （alprazolam）. In the control group, the patients were given routine treatments of antacid, prokinetics, etc. Before and after 8-week treatment, the following examinations were performed： ① The gastrointestinal symptoms were assessed according to the symptoms; ② The severity of depression was evaluated with Hamilton depression scale （HAMD）; ③The relaxation of proximal stomach was observed using water load test; ④ The serum level of cortisol was detected.MAIN OUTCOME MEASURES： ① Symptom score; ② HAMD score; ③ Water load amount; ④Serum level of cortisol.RESULTS： All the 45 patients were involved in the analysis of results. ① Symptom score： The scores of gastrointestinal symptoms were decreased as compared with those before treatment in both the treatment group and control group （P 〈 0.05）. ② HAMD scores： The scores of HAMD were decreased as compared with those before treatment in both the treatment group and control group （P 〈 0.05）. ③ Water load amount：The total effective rate was significantly higher in the treatment group than the control group （P 〈 0.05）. ④The serum levels of cortisol after treatment were significantly lower than those before treatment in the patients with severe gastrointestinal symptoms in the treatment group and control group （P 〈 0.05）.CONCLUSION： Antidepressants can normalize the cortisol level of patients with functional dyspepsia, and then decrease gastric sensitivity and ameliorates the receptive relaxation of proximal stomach, also increase the water load amount correspondingly, and finally control the gastrointestinal symptoms of functional dyspepsia.展开更多
基金supported by the National Natural Science Foundation of China(Grants No.52175088 and 52172399)the National Outstanding Youth Science Fund(NOYSF)in China(Grant No.52325211)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY19E050012).
文摘load model established in a road traffic scene is difficult to adapt to the changes of the surrounding road environment during the actual Objective:At present,most research on driver mental load identification is based on a single driving scene.However,the driver mental driving process.We proposed a driver mental load identification model which adapts to urban road traffie scenarios.scene discrimination sub-model can quickly and accurately determine the road traffic scene.The driver load identification sub-model Methods:The model includes a driving scene discrimination sub-model and driver load identification sub-model,in which the driving sub-model.selects the best feature subset and the best model algorithm in the scene based on the judgement of the driving scene classification Results:The results show that the driving scene discrimination sub-model using five vehicle features as feature subsets has the best performance.The driver load identification sub-model based on the best feature subset reduces the feature noise,and the recognition tends to be consistent,and the support vector machine(5VM)algorithm is better than the K-nearest neighbors(KNN)algorithm.effect is better than the feature set using a single source signal and all data.The best recognition algorithm in different scenarios Conclusion:The proposed driver mental load identificution model can discriminate the driving scene quickly and accurately,and then identify the driver mental load.In this way,our model can be more suitable for actual driving and improve the effect of driver mental load identification.
文摘互通式立交承担着不同方向交通流的流向转换功能,是道路交通网络的重要节点。目前高密度立交在城市道路网络中已愈发常见,高密度立交之间的间距比普通立交更小,车辆交织更为密集,驾驶人需要在更短的时间内进行分合流驾驶操作。为探究立交间距对驾驶人精神负荷的影响与高密度立交出入口区段的驾驶人精神负荷统计特性,在重庆市内环快速路上选择了1段包含4座连续立交的路段作为实验对象,其中3座立交为高密度立交。通过车载仪器采集47名驾驶人在实车实验过程中的心电数据,对在高密度立交出入口区段与普通间距立交出入口区段的驾驶人心率变异性时域和频域指标进行差异性分析,得到了驾驶人在高密度立交与普通间距立交出入口区段的精神负荷分布特征。研究结果表明:驾驶人在经过普通间距立交出入口区段和高密度立交出入口区段时的心率变异性时域指标不存在显著性差异,频域指标心率变异性的低、高频功率的比值(ratio of low-frequency to high-frequency,LF/HF)存在显著性差异,频域指标LF/HF可作为评价驾驶人精神负荷在立交出入口区段的主要指标;驾驶人在经过高密度立交入口区段时,频域指标LF/HF比经过普通间距立交入口区段时显著增加,立交间距不足会增加驾驶人在立交入口区段的精神负荷;驾驶人在经过普通间距立交出口区段时的心率变异性频域指标LF/HF比经过高密度立交出口区段时显著增加,即驾驶人通过普通间距立交出口区段的精神负荷更大;对于高密度立交群,驾驶人在入口区段的精神负荷水平要略高于出口区段。
文摘近年来,随着人工智能领域技术的不断发展,人机交互领域吸引了更多学者的关注。研究表明由脑电图(electroencephalogram,EEG)提取的特征功率谱密度对于脑力负荷的变化比较敏感,但由于其维数过高,容易造成数据灾难。局部线性嵌入(locally linear embedding,LLE)是常用的非线性降维算法,该算法弥补了传统线性降维算法无法发现数据中非线性结构关系的不足。由于不同数据集中样本分布的稀疏程度和扭曲程度不同,在使用LLE对不同数据集进行降维时的最佳邻域参数也不同。利用样本点之间的欧氏距离和测地距离的关系量化了数据集的扭曲程度,自适应邻域参数的局部线性嵌入算法(variable k-locally linear embedding,VK-LLE)动态地调整每一个数据集的最佳邻域参数,解决了样本分布扭曲程度不同对降维效果造成的干扰。实验结果表明,经过VK-LLE降维后的数据使用支持向量机(support vector machine,SVM)分类精度普遍高于经过传统LLE的降维后再使用SVM分类的精度,对复杂数据集有更强的适应能力。
文摘要为明确高密度互通立交行驶环境下,主线车流量对出入口区段驾驶人精神负荷间的影响,在重庆市内环快速路高密度互通立交群进行自然驾驶实车试验,使用Physiolab生理检测仪连续采集驾驶人在行驶过程中的心电数据,用于统计各驾驶人的心率指标变化情况。本次试验基于主成分分析法选择心率变异率指标RMSSD(root mean square of successive differences)、LFnorm(low frequency norm)、HFnorm(high frequency norm)、LF(low frequency)/HF(high frequency)以及心率突变率指标HRMR(heat ratemutation rate)作为驾驶人精神负荷的评价指标,记为主成分F 1和主成分F 2,并建立评价模型。结果表明:驾驶人在小净距立交出入口区段行驶时,立交主线车流量的大小会影响驾驶人的精神负荷;当驾驶人驶入立交主线时,三次模型对入口段车流量与主成分F 2的拟合效果最好,呈开口向上的三次曲线,曲线谷值点出现在2级流量水平处,模型显著;当驾驶人驶出立交主线时,一次线性模型对出口段车流量与主成分F 1的拟合效果最好,模型显著。
文摘BACKGROUND： It has been demonstrated that patients with functional dyspepsia have experiences social life stress events, and accompanied by psychological disorders, mainly manifested as depression and anxiety.Mental factors can lead to excessive gastrointestinal consensual reaction, and result in different brain-gut axis disturbance, and then cause the gastrointestinal sensorimotor abnormality and endocrine changes.OBJECTIVE： To observe the effect of antidepressant treatment on the changes of water load and serum cortisol in patients with functional dyspepsia, and analyze the therapeutic mechanism.DESIGN： A comparative observation.SETTING： The First Affiliated Hospital o Zhengzhou University.PARTICIPANTS： Forty-five patients with functional dyspepsia accompanied by depression were selected from the Department of Gastroenterology, the First Affiliated Hospital of Zhengzhou University from July 2004 to July 2006, and they were 25 - 65 years of age, and their disease courses ranged 1 - 10 years. They were all accorded with the diagnostic standards for Rome Ⅱ functional dyspepsia functional dyspepsia. As the patients＇ will, they were divided into treatment group （n =30, 12 males and 18 females） and control group （n =15, 6 males and 9 females）, and there were no significant differences in the data between the two groups （P 〉 0.05）. The programs were discussed and agreed by the committee of medical ethics of the First Affiliated Hospital of Zhengzhou University. Informed contents were obtained from all the patients.METHODS： In the treatment group, the patients were treated with venlafaxine sustained release capsule （75 mg per day）, and those with sleep disorder were added by benzodiazepines （alprazolam）. In the control group, the patients were given routine treatments of antacid, prokinetics, etc. Before and after 8-week treatment, the following examinations were performed： ① The gastrointestinal symptoms were assessed according to the symptoms; ② The severity of depression was evaluated with Hamilton depression scale （HAMD）; ③The relaxation of proximal stomach was observed using water load test; ④ The serum level of cortisol was detected.MAIN OUTCOME MEASURES： ① Symptom score; ② HAMD score; ③ Water load amount; ④Serum level of cortisol.RESULTS： All the 45 patients were involved in the analysis of results. ① Symptom score： The scores of gastrointestinal symptoms were decreased as compared with those before treatment in both the treatment group and control group （P 〈 0.05）. ② HAMD scores： The scores of HAMD were decreased as compared with those before treatment in both the treatment group and control group （P 〈 0.05）. ③ Water load amount：The total effective rate was significantly higher in the treatment group than the control group （P 〈 0.05）. ④The serum levels of cortisol after treatment were significantly lower than those before treatment in the patients with severe gastrointestinal symptoms in the treatment group and control group （P 〈 0.05）.CONCLUSION： Antidepressants can normalize the cortisol level of patients with functional dyspepsia, and then decrease gastric sensitivity and ameliorates the receptive relaxation of proximal stomach, also increase the water load amount correspondingly, and finally control the gastrointestinal symptoms of functional dyspepsia.
