期刊文献+
共找到589篇文章
< 1 2 30 >
每页显示 20 50 100
Changes in brain activation patterns according to cross-training effect in serial reaction time task An functional MRI study
1
作者 Yong Hyun Kwon Jung Won Kwon Ji Won Park 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第7期639-646,共8页
Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral l... Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function (i.e., primary motor cortex, premotor area, posterior parietal cortex) showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the opposite homologous limb, and motor skill acquisition of the untrained limb led to changes in brain activation patterns in the cerebral cortex and cerebellum. 展开更多
关键词 neural regeneration neuroimaging cross-training effects motor skill learning cortical activation cerebellar activation serial reaction time task functional MRI response time response accuracy primary motor cortex dentate nucleus VERMIS grants-supported paper photographs-containingpaper NEUROREGENERATION
下载PDF
Aging effects of regional activation in a spatial task A functional magnetic resonance imaging study 被引量:1
2
作者 Jong-Rak Park Dae-Woon Lim +6 位作者 Mi-Hyun Choi Su-Jeong Lee Jin-Seung Choi Hyung-Sik Kim Jeong-Han Yi Gye-Rae Tack Soon-Cheol Chung 《Neural Regeneration Research》 SCIE CAS CSCD 2009年第9期663-667,共5页
BACKGROUND: An increasing number of studies have shown the effects of aging in basic cognitive processing and higher cognitive functions using functional magnetic resonance imaging (fMRI). However, little is known ... BACKGROUND: An increasing number of studies have shown the effects of aging in basic cognitive processing and higher cognitive functions using functional magnetic resonance imaging (fMRI). However, little is known about the aging effects in diverse cognitive abilities, such as spatial learning and reasoning. OBJECTIVE: To investigate the effect of aging on spatial cognitive performance and regional brain activation based on fMRI. DESIGN, TIME, AND SETTING: A block design for fMRI observation. This study was performed at the fMRI Laboratory, Brain Science Research Center, Korea Advanced Institute of Science and Technology from March 2006 to May 2009. PARTICIPANTS: Eight right-handed, male, college students in their 20s (mean age 21.5 years) and six right-handed, male, adults in their 40s (mean age 45.7 years), who graduated from college, participated in the study. All subjects were healthy and had no prior history of psychiatric or neurological disorders. METHODS: A spatial task was presented while brain images were acquired using a 3T fMRI system (ISOL Technology, Korea). The spatial tasks involved selecting a shape that corresponded to a given figure using four examples, as well as selecting a development figure of a diagram. MAIN OUTCOME MEASURES: The accuracy rate (number of correct answers/total number of items x 100%) of spatial tasks was calculated. Using the subtraction procedure, the activated areas in the brain during spatial tasks were color-coded by T-score. The double subtraction method was used to analyze the effect of aging between the two age groups (20s versus 40s). RESULTS: The cerebellum, occipital lobe, parietal lobe, and frontal lobe were similarly activated in the two age groups. Increased brain activations, however, were observed in bilateral parietal and superior frontal lobes of the younger group. More activation was observed in bilateral middle frontal and right inferior frontal lobes in the older group. Compared with the older group, the younger men exhibited greater spatial performance (P = 0.012). CONCLUSION: Reduced cognitive function correlated with decreased activation areas in the parietal lobe and altered activation in the frontal lobe. 展开更多
关键词 functional magnetic resonance imaging AGING regional activation spatial task
下载PDF
Effects of task orientation on subsequent source memory as revealed by functional MRI
3
作者 Xiuyan Guo Lei Zhu +3 位作者 Li Zheng Jianqi Li Qianfeng Wang Zhiliang Yang 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第26期2424-2431,共8页
Episodic memories are composed of various interrelated elements, including those specific to items of central interest and those pertaining to related features, such as the color, shape, size, spatial location, tempor... Episodic memories are composed of various interrelated elements, including those specific to items of central interest and those pertaining to related features, such as the color, shape, size, spatial location, temporal order, and media or modalities of presentation. Memory about a core item (such as a word, object, or picture) is called item memory while memory about the context or related fea- tures of a core item is defined as source memory. What determines which sources within an episode are successfully remembered is of particular interest to researchers. Behavioral evidence suggests that the orientation of a memory task influences whether the related source of the item will be re- membered later. This study explored changes in the hippocampus and prefrontal cortex while par- ticipants completed two tasks: an item-oriented task and a source-oriented task. We used functional MRI to investigate the neural mechanisms by which task orientation influences source encoding. We found that subsequent source memory effects in the right prefrontal cortex and hippocampus were modulated by task orientation, whereas task orientation modulated item memory effects in the prefrontal cortex. These findings highlight the possibility that the hippocampus contributes to the intentional encoding of item-source associations, whereas the prefrontal cortex is biased toward processing information to which attention is directed. 展开更多
关键词 neural regeneration NEUROPSYCHOLOGY learning source memory task orientation hippocampus prefrontal cortex functional MRI grants-supported paper NEUROREGENERATION
下载PDF
运动成瘾人群的奖赏与抑制功能神经网络的fMRI研究
4
作者 钱征 丁庆国 +3 位作者 梁沛 李琴 张红强 孙佳斌 《中国中西医结合影像学杂志》 2024年第3期282-285,289,共5页
目的:利用fMRI研究运动成瘾人群的奖赏与抑制功能神经网路。方法:采用运动成瘾量表(EAI)筛选出29例运动成瘾者(成瘾组),平均年龄(45.6±4.3)岁;招募26例性别、年龄、平均受教育水平相匹配的非运动成瘾者(对照组),平均年龄(45.7±... 目的:利用fMRI研究运动成瘾人群的奖赏与抑制功能神经网路。方法:采用运动成瘾量表(EAI)筛选出29例运动成瘾者(成瘾组),平均年龄(45.6±4.3)岁;招募26例性别、年龄、平均受教育水平相匹配的非运动成瘾者(对照组),平均年龄(45.7±5.6)岁。采用相关线索刺激和Go/NoGo行为任务范式;2组在观看运动相关图片和执行Go/NoGo任务下行fMRI扫描。结果:线索刺激脑激活状态分析结果显示,成瘾组在观看运动图片时奖赏网络激活显著增强,表现为左侧额上回、左侧额中回、左侧额下回和右侧前扣带皮质脑区活动增强。Go与NoGo任务条件下的脑激活状态对比显示,对照组存在显著的抑制性负激活脑区,包括右侧颞上回、右侧中央后回、左侧中央后回、左侧缘上回、右侧中央前回等(均P<0.01),而成瘾组仅显示左侧中央后回的负激活显著(P<0.01)。结论:运动成瘾人群对运动线索刺激的奖赏网络激活显著增强,而执行神经网络的抑制功能反应明显减弱。 展开更多
关键词 运动成瘾 线索相关刺激 Go/NoGo任务 功能磁共振成像
下载PDF
Correlation between LIFG and Autonomic Activation during Stressful Tasks:A Functional Near-infrared Spectroscopy (fNIRS) Study 被引量:1
5
作者 史洁 酒谷薰 +2 位作者 冈本雅子 山口由衣 左焕琮 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2014年第5期663-671,共9页
It remains unclear whether language tasks in one's first (L1) or second (L2) language can cause stress responses and whether frontal, autonomic and behavioral responses to stressful tasks are correlated. In this ... It remains unclear whether language tasks in one's first (L1) or second (L2) language can cause stress responses and whether frontal, autonomic and behavioral responses to stressful tasks are correlated. In this study, we studied 22 Chinese subjects whose L2 was English and measured the cerebral blood oxygenation in their frontal lobe by using functional near-infrared spectroscopy (fNIRS) as par- ticipants engaged in a mental arithmetic task (MAT) and verbal fluency tasks (VFTs) in L1 (Chinese) and L2 (English). To examine the activated cortical areas, we estimated the channel location based on Montreal Neurological Institute (MNI) standard brain space by using a-probabilistic estimation method. We evaluated heart rate (HR) changes to analyze autonomic nervous system (ANS) functioning. We found that the MAT and VFTs induced greater increases in HR than did the control (Ctrl) task. Further- more, subjects developed greater increases in HR in the MAT and VFTt~ than they did in the VFTL1. Compared with the Ctrl task, the MAT and both VFTLland VFTL2 produced robust and widespread bi- lateral activation of the frontal cortex. Interestingly, partial correlation analysis indicated that the activity in the left inferior frontal gyrus (LIFG) [Brodmarm's area (BA) 47] was consistently correlated with the increases in HR across the three tasks (MAT, VFTL2, and VFTL1), after controlling for the performance data. The present results suggested that a VFT in L2 may be more stressful than in L1. The LIFG may affect the activation of the sympathetic system induced by stressful tasks, includin~ MATs and VFTs. 展开更多
关键词 functional near-infrared spectroscopy mental arithmetic task verbal fluency task auto-nomic nervous system inferior frontal gyrus
下载PDF
Functional magnetic resonance imaging of cerebellar activation and lateralization during verbal and visuospatial tasks
6
作者 Mi-Hyun Choi Su-Jeong Lee +9 位作者 Jae-Woong Yang Jin-Seung Choi Hyung-Sik Kim Jeong-Han Yi Gye-Rae Tack Soon-Cheol Chung Byung-Chan Min Se-Jin Park Jong-Rak Park Jae-Hoon Jun 《Neural Regeneration Research》 SCIE CAS CSCD 2010年第3期226-231,共6页
BACKGROUND: Previous studies have analyzed cerebral activation and lateralization of cognitive functions, as well as cerebellar function with reference to high-level cognitive processing. However, there has been very... BACKGROUND: Previous studies have analyzed cerebral activation and lateralization of cognitive functions, as well as cerebellar function with reference to high-level cognitive processing. However, there has been very little research on systematization and diversification. In particular, there are no reports on cerebellar lateralization, although reliable results have been reported on cerebral lateralization. OBJECTIVE: This study analyzed cerebellar activation and lateralization in relation to verbal and visuospatial tasks using functional magnetic resonance imaging (fMRI). DESIGN, TIME AND SETTING: A block design for fMRI observation was performed at the fMRI Laboratory, Brain Science Research Center, Korea Advanced Institute of Science and Technology from May 2006 to September 2008. PARTICIPANTS: Sixteen healthy, male, college students, aged (23.3 ± 0.5) years, and 16 healthy, male, college students, aged (21.5 ± 2.3) years, participated in the study, respectively. METHODS: Verbal and visuospatial tasks were presented while functional brain images were acquired using a 3T fMRI system. Verbal analogy testing required the subject to select the word with the same relationship as one of the given words. Verbal antonym testing required the subject to select the word with a different meaning among four words. Visuospatial tasks involved selecting a shape that corresponded to a given figure with four examples, as well as selecting a development figure of a diagram. MAIN OUTCOME MEASURES: Changes in cerebellar activation and lateralization between two cognition tasks. RESULTS: Bilateral hemisphere Iobules VI and IX, right hemisphere Iobule VIII, bilateral hemisphere Iobules Crus I, and vermis Iobule IV, V, and Vl were closely related to verbal tasks in comparison to visuospatial tasks. Conversely, bilateral hemisphere Iobules IV and V, as well as the right hemisphere Iobule VI, were closely related to visuospatial tasks compared to verbal tasks. There was no great difference between the number of activated voxels in the cerebellums during the tasks, and cerebellar lateralization was not observed. CONCLUSION: In the cerebellum, the activation region, but not lateralization, was different between verbal and visuospatial tasks. 展开更多
关键词 CEREBELLUM LATERALIZATION functional magnetic resonance imaging verbal and visuospatial tasks neuroimaging neural regeneration
下载PDF
健康操与认知任务训练在帕金森伴认知障碍患者中的应用
7
作者 陈德芳 陈炜 +1 位作者 王桂云 成红霞 《中国卫生标准管理》 2024年第9期176-180,共5页
目的探讨健康操结合认知任务训练在帕金森合并轻度认知障碍(Parkinson's disease with mild cognitive impairment,PD-MCI)患者中的应用效果。方法选取南通市第四人民医院2021年9月—2023年3月收治的PD-MCI患者90例,依照随机分配原... 目的探讨健康操结合认知任务训练在帕金森合并轻度认知障碍(Parkinson's disease with mild cognitive impairment,PD-MCI)患者中的应用效果。方法选取南通市第四人民医院2021年9月—2023年3月收治的PD-MCI患者90例,依照随机分配原则分为2组,各45例。对照组采取常规健康教育及常规训练,观察组在上述基础上采取健康操结合认知任务训练,为期6个月。对比2组干预前后认知功能[蒙特利尔认知评估量表(Montreal cognitive assessment,MoCA)、简易精神状态检查量表(mini-mental state examination,MMSE)评分]、跌倒风险[修订版跌倒效能量表(modified fall efficacy scale,MFES)评分]、运动功能[帕金森综合评分量表3(unified Parkinson's disease rating scale-Ⅲ,UPDRS-Ⅲ)评分]、平衡能力[起立-行走测试(timed up and go test,TUG)]。结果干预后,观察组MoCA、MMSE评分分别为(23.81±2.30)分、(23.59±1.80)分,较干预前升高,且高于对照组的(20.13±2.55)分、(20.78±2.32)分(P<0.05)。干预后,2组MFES评分较干预前升高,观察组为(7.34±0.59)分,高于对照组的(6.42±0.77)分(P<0.05);2组UPDRS-Ⅲ评分较干预前下降,观察组为(16.52±2.21)分,低于对照组的(18.15±2.04)分(P<0.05)。干预后,2组单任务TUG、双任务TUG时间均较干预前缩短,观察组为(11.44±0.70)s、(18.39±1.44)s,短于对照组的(13.54±1.26)s、(21.26±1.53)s(P<0.05)。结论健康操结合认知任务训练在PD-MCI患者中应用效果良好,能改善患者认知功能和运动功能,提高平衡能力,降低跌倒风险。 展开更多
关键词 帕金森 轻度认知障碍 健康操 认知任务训练 认知功能 运动功能 平衡能力
下载PDF
“三全育人”视域下高校辅导员职能的泛化与回归
8
作者 张阳 翁伟斌 《教育理论与实践》 北大核心 2024年第9期51-55,共5页
基于习近平总书记“育人的根本在于立德”的重要论述和高校“三全育人”综合改革的实践要求,高校辅导员存在职能泛化现象,即角色定位模糊,职责边界不明;高校思政工作整体规划不够,法治化程度有待提高;队伍配比设置不到位不科学致使辅导... 基于习近平总书记“育人的根本在于立德”的重要论述和高校“三全育人”综合改革的实践要求,高校辅导员存在职能泛化现象,即角色定位模糊,职责边界不明;高校思政工作整体规划不够,法治化程度有待提高;队伍配比设置不到位不科学致使辅导员工作分工失衡;学生工作的复杂性导致辅导员职能难以聚焦。实现高校辅导员职能的有效回归,可以在“大思政”格局中明确辅导员职能任务、增强主体性、提升核心能力、营造辅导员发展的良好氛围。 展开更多
关键词 高校辅导员 “三全育人” 大思政 职能回归 身份回归 主体性 价值回归 职能任务
下载PDF
Brain functional network connectivity based on a visual task: visual information processing-related brain regions are significantly activated in the task state 被引量:1
9
作者 Yan-li Yang Hong-xia Deng +2 位作者 Gui-yang Xing Xiao-luan Xia Hai-fang Li 《Neural Regeneration Research》 SCIE CAS CSCD 2015年第2期298-307,共10页
It is not clear whether the method used in functional brain-network related research can be applied to explore the feature binding mechanism of visual perception. In this study, we inves-tigated feature binding of col... It is not clear whether the method used in functional brain-network related research can be applied to explore the feature binding mechanism of visual perception. In this study, we inves-tigated feature binding of color and shape in visual perception. Functional magnetic resonance imaging data were collected from 38 healthy volunteers at rest and while performing a visual perception task to construct brain networks active during resting and task states. Results showed that brain regions involved in visual information processing were obviously activated during the task. The components were partitioned using a greedy algorithm, indicating the visual network existed during the resting state.Z-values in the vision-related brain regions were calculated, conifrming the dynamic balance of the brain network. Connectivity between brain regions was determined, and the result showed that occipital and lingual gyri were stable brain regions in the visual system network, the parietal lobe played a very important role in the binding process of color features and shape features, and the fusiform and inferior temporal gyri were crucial for processing color and shape information. Experimental ifndings indicate that understanding visual feature binding and cognitive processes will help establish computational models of vision, improve image recognition technology, and provide a new theoretical mechanism for feature binding in visual perception. 展开更多
关键词 nerve regeneration functional magnetic resonance imaging resting state task state brain network module division feature binding Fisher’s Z transform CONNECTIVITY visual stimuli NSFC grants neural regeneration
下载PDF
认知-运动双重任务训练对老年血管性轻度认知障碍病人认知状态及步行能力的影响
10
作者 张莹 寇京莉 +2 位作者 孙雪枫 欧洲 张佟 《循证护理》 2024年第7期1287-1290,共4页
目的:探究认知-运动双重任务训练对老年血管性轻度认知障碍(VaMCI)病人认知状态及步行能力的影响。方法:选取我院2021年4月—2022年4月收治80例老年VaMCI病人作为研究对象,依据训练方式不同分为常规训练组和双重任务组,各40例。常规训... 目的:探究认知-运动双重任务训练对老年血管性轻度认知障碍(VaMCI)病人认知状态及步行能力的影响。方法:选取我院2021年4月—2022年4月收治80例老年VaMCI病人作为研究对象,依据训练方式不同分为常规训练组和双重任务组,各40例。常规训练组给予常规认知功能训练,双重任务组给予认知-运动双重任务训练,干预3个月后比较两组病人认知状态、步行能力、跌倒风险控制。结果:干预后,双重任务组临床痴呆量表(CDR)评分低于常规训练组,简易精神状态量表(MMSE)评分高于常规训练组(P<0.05),改良Barthel指数(MBI)评分、步频、步速水平高于常规训练组(P<0.05),修订版跌倒功效量表(MFES)、Berg平衡量表(BBS)评分高于常规训练组(P<0.05)。结论:认知-运动双重任务训练可改善老年VaMCI病人的认知状态,调控跌倒风险控制水平,调节步行能力。 展开更多
关键词 认知-运动双重任务训练 血管性轻度认知障碍 认知功能 老年人 护理
下载PDF
任务匹配系统中高效可撤销属性加密方案
11
作者 董国芳 张楚雯 +2 位作者 常远 鲁烨堃 刘兵 《云南民族大学学报(自然科学版)》 CAS 2024年第4期478-485,共8页
针对传统任务匹配系统中数据处理存在的安全隐私和成本开销问题,提出了一种适用于资源有限系统的高效可撤销外包密文策略属性加密方案.通过将传统的加密分为用户离线和在线加密阶段两部分实现快速加密,并将密文外包给云服务器再与区块... 针对传统任务匹配系统中数据处理存在的安全隐私和成本开销问题,提出了一种适用于资源有限系统的高效可撤销外包密文策略属性加密方案.通过将传统的加密分为用户离线和在线加密阶段两部分实现快速加密,并将密文外包给云服务器再与区块链建立联系以降低用户计算成本,最后利用变色龙哈希函数更新用户私钥进行属性撤销和用户撤销两类细粒度撤销.最后通过实验表明,该方案与现有可撤销属性加密方案相比,可以抵御密钥泄露和共谋攻击,且具有更低的时间开销. 展开更多
关键词 变色龙哈希函数 外包解密 可撤销 属性加密 任务匹配
下载PDF
基于多任务学习的间质性肺病分割算法
12
作者 李威 陈玲 +8 位作者 徐修远 朱敏 郭际香 周凯 牛颢 张煜宸 易珊烨 章毅 罗凤鸣 《计算机应用》 CSCD 北大核心 2024年第4期1285-1293,共9页
间质性肺病(ILD)的分割标签标注成本极高,且现有数据集通常存在样本量较少的问题,导致训练的模型效果较差。针对该问题,提出一种基于多任务学习的ILD分割算法。首先,基于U-Net构建多任务分割模型;其次,使用生成的肺部分割标签作为辅助... 间质性肺病(ILD)的分割标签标注成本极高,且现有数据集通常存在样本量较少的问题,导致训练的模型效果较差。针对该问题,提出一种基于多任务学习的ILD分割算法。首先,基于U-Net构建多任务分割模型;其次,使用生成的肺部分割标签作为辅助任务标签进行多任务学习;最后,使用一种自适应调整多任务损失函数权重的方法,平衡主任务和辅助任务的损失。在自构建的ILD数据集上的实验结果表明,多任务分割模型的Dice相似系数(DSC)达到了82.61%,与U-Net相比提升了2.26个百分点。验证了所提算法可以提升ILD的分割性能,协助临床医生进行ILD诊断。 展开更多
关键词 间质性肺病 语义分割 小样本量 多任务学习 自适应多任务损失函数
下载PDF
基于CT图像的深度神经网络肺功能预测
13
作者 杜秋雨 陈楠 +3 位作者 郭际香 章毅 刘伦旭 徐修远 《四川大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第4期145-154,共10页
我国流行病学调查结果显示,以慢阻肺和哮喘为代表的慢性呼吸系统疾病患病率高且呈现上升的趋势,给公共卫生健康带来了严重威胁.目前,计算机断层扫描(CT)作为一种方便、无创的方法被广泛应用于肺功能的评估.在基于CT图像的计算机辅助评... 我国流行病学调查结果显示,以慢阻肺和哮喘为代表的慢性呼吸系统疾病患病率高且呈现上升的趋势,给公共卫生健康带来了严重威胁.目前,计算机断层扫描(CT)作为一种方便、无创的方法被广泛应用于肺功能的评估.在基于CT图像的计算机辅助评估肺功能的方法中,人工设计的特征存在表达能力有限的问题,且现有的深度学习方法从高噪稀疏的小样本数据集中提取特征的效果较差.为了提高肺功能检查的效率,本文提出了基于CT图像的肺功能预测网络(LFP-ResNet).首先,本文提出了多层次上下文特征融合(MCFF)方法,有效增强了对表征肺部纹理和形态的特征提取;其次,利用三维残差网络充分保证了CT图像的空间异质性;最后,本文构建了包含肺功能正常人群和患有慢性呼吸系统疾病患者的肺功能数据集,并在该数据集上对比了本工作提出的方法以及其他先进的肺功能预测方法 .实验结果表明,本文提出的MCFF策略在含噪声的稀疏矩阵中提取特征时比其他特征提取方法更有效,且所构建的LFP-ResNet在肺功能预测任务中表现出更好的预测性能. 展开更多
关键词 计算机断层扫描 深度学习 多任务学习 肺功能检查 慢性阻塞性肺疾病
下载PDF
综合行政执法改革过程中的多维结构变迁与能动者策略 被引量:1
14
作者 叶贵仁 蔡龚涛 《理论与改革》 北大核心 2024年第1期152-165,168,共15页
推动执法权属地化与综合化是夯实基层政权建设的重要一环,但在政策实践中,并不必然带来治理效能的提升。事权下放后,基层治理结构的实质性变革如何形塑执法主体的行为策略,以提升事权承接的有效性,是亟待回答的重要议题。文章从“结构... 推动执法权属地化与综合化是夯实基层政权建设的重要一环,但在政策实践中,并不必然带来治理效能的提升。事权下放后,基层治理结构的实质性变革如何形塑执法主体的行为策略,以提升事权承接的有效性,是亟待回答的重要议题。文章从“结构—过程—功能”的视角出发,对一个街道综合行政执法体制改革进行系统考察,构建理解多维结构变迁中能动者策略生成的分析框架。研究发现,在改革过程中,综合执法部门所嵌入的横向结构在权力、责任和资源维度发生系统性变迁。执法主体在基层治理结构所设定的规则约束与行动空间中,基于复杂性和概率性两个维度,划分四种类型的执法任务,并能动地创设动员式、裁剪式、扩容式等执法策略,衔接再配置的结构性要素与复杂外部事务治理环节,从而有效回应“块块”运作规则和事权下放的内在要求。 展开更多
关键词 综合行政执法 结构功能主义 能动者策略 基层治理 执法任务
下载PDF
面向多智能体与双层卸载的车联网卸载算法
15
作者 张冀 龚雯雯 +1 位作者 朵春红 齐国梁 《计算机工程》 CAS CSCD 北大核心 2024年第8期182-197,共16页
在车联网(IoV)边缘计算环境中,针对如何高效地进行任务卸载和资源分配来缓解移动车辆存储和计算能力有限的问题,提出多智能体与双层卸载的IoV卸载算法。首先,提出移动边缘计算(MEC)服务器与车辆以及空闲车辆(MEC-V-NTVC)互联的3层网络模... 在车联网(IoV)边缘计算环境中,针对如何高效地进行任务卸载和资源分配来缓解移动车辆存储和计算能力有限的问题,提出多智能体与双层卸载的IoV卸载算法。首先,提出移动边缘计算(MEC)服务器与车辆以及空闲车辆(MEC-V-NTVC)互联的3层网络模型,建立了任务模型、判断模型和计算模型;其次,将任务车辆的计算卸载以及资源分配抽象成部分可观测马尔可夫决策过程(POMDP),并提出双层卸载机制以达到最小化系统总成本的目的。基于空闲车辆云以及单调值函数分解QMIX,提出一种基于双层卸载机制的深度强化学习卸载算法DLSQMIX。该算法协调任务车辆、空闲车辆以及环境信息,在考虑车辆任务时间约束的情况下,充分利用MEC服务器以及空闲车辆的计算能力,求得系统最优卸载决策。从边缘服务器、空闲车辆的计算能力、任务车辆、空闲车辆的数量以及平均任务量等方面对系统开销和时延进行对比。仿真实验结果表明,DLSQMIX算法能够有效求解任务卸载问题,与遗传算法(GA)、粒子群优化(PSO)算法以及QMIX算法相比,所提算法的系统开销减小2.52%~3.91%,时延降低3.50%~6.59%。 展开更多
关键词 车联网 边缘计算 空闲车辆云 双层卸载机制 单调值函数分解
下载PDF
对侧功能性电刺激与任务导向性训练不同方式联用对脑卒中手功能的影响 被引量:1
16
作者 张敏杰 金星 +3 位作者 孟兆祥 王鑫 王建建 柯明慧 《中国康复》 2024年第2期67-71,共5页
目的:研究对侧控制型电刺激(CCFES)与任务导向性训练不同方式联用对脑卒中患者手功能恢复的影响。方法:选取我院病程在1个月内的60例脑卒中患者,将其按随机数字法分为同步组即CCFES与任务导向性训练同步进行(30例)与分步组即CCFES治疗... 目的:研究对侧控制型电刺激(CCFES)与任务导向性训练不同方式联用对脑卒中患者手功能恢复的影响。方法:选取我院病程在1个月内的60例脑卒中患者,将其按随机数字法分为同步组即CCFES与任务导向性训练同步进行(30例)与分步组即CCFES治疗后序贯进行任务导向型训练(30例)。于入组前、治疗4周后分别采用Fugl-Meyer运动功能评分(FMA)、Wolf运动功能测试量表(WMFT)、表面肌电图(sEMG)及Barthel指数(BI)对患者的上肢、腕手运动功能及日常生活独立性进行评定。结果:治疗后2组RMS比值、FMA、WMFT及BI评分均较治疗前明显提高(P<0.01,0.05),且同步组各项评定较分步组更高(P<0.01,0.05)。结论:CCFES与任务导向性训练同步组在改善脑卒中患者的上肢及手功能更有优势。 展开更多
关键词 对侧控制型功能性电刺激 任务导向性训练 脑卒中 手功能 双侧对称运动
下载PDF
基于多任务学习的近岸舰船检测方法
17
作者 刘馨嫔 王洪 赵良瑾 《计算机与现代化》 2024年第3期29-33,共5页
在遥感光学图像近岸舰船目标检测任务中,针对近岸复杂场景中存在形状近似目标的虚警问题,提出一种基于多任务学习的近岸舰船目标检测方法。该方法通过构建海陆分割任务与舰船检测任务并行双路框架,将传统的任务串行处理流程优化为并行... 在遥感光学图像近岸舰船目标检测任务中,针对近岸复杂场景中存在形状近似目标的虚警问题,提出一种基于多任务学习的近岸舰船目标检测方法。该方法通过构建海陆分割任务与舰船检测任务并行双路框架,将传统的任务串行处理流程优化为并行处理方式,设计联合损失函数进行双路优化训练约束,提升模型训练的稳定性,通过双分支融合模块剔除陆地掩膜中的检测结果,实现陆地虚警滤除。采用谷歌地球遥感图像制作的数据集进行实验,将本文提出的方法与单任务检测算法YOLOv5相比,mAP提升了4.4个百分点,虚警率降低了3.4个百分点。实验结果表明本文算法对陆地虚警抑制有效。 展开更多
关键词 舰船检测 海陆分割 多任务学习 损失函数
下载PDF
基于逆强化学习与行为树的机械臂复杂操作技能学习方法 被引量:1
18
作者 宋越杰 马陈昊 +1 位作者 孟子晗 刘元归 《现代电子技术》 北大核心 2024年第7期133-139,共7页
现有分层强化学习方法不仅在学习过程中存在样本效率低、奖励稀疏以及学习时间过长等问题,而且大多基于仿真环境,导致学习策略在机器人真实操作环境中部署困难。针对上述问题,提出一种基于逆强化学习与行为树的机械臂复杂操作技能学习... 现有分层强化学习方法不仅在学习过程中存在样本效率低、奖励稀疏以及学习时间过长等问题,而且大多基于仿真环境,导致学习策略在机器人真实操作环境中部署困难。针对上述问题,提出一种基于逆强化学习与行为树的机械臂复杂操作技能学习方法。在对复杂操作任务进行分割的基础上,首先,根据专家演示轨迹确定分割后每个子任务的强化学习参数及其对应的专家策略;其次,根据子任务专家策略并使用生成对抗模仿学习算法进行预训练,得到每个子任务的奖励函数;再次,运用每个子任务的奖励函数并基于SAC算法做进一步训练,获取到每个子任务的最优策略;最后,将子任务最优策略从仿真环境部署到真实环境,并将部署后的每个子任务作为叶节点构建行为树,实现机械臂复杂任务规划。实验结果表明,所提方法能较好地学习机械臂复杂操作技能,并在性能上优于其他传统强化学习算法。 展开更多
关键词 机械臂 逆强化学习 行为树 复杂操作任务 专家策略 奖励函数
下载PDF
基于多任务自适应知识蒸馏的语音增强
19
作者 张刚敏 李雅荣 +2 位作者 贾海蓉 王鲜霞 段淑斐 《太原理工大学学报》 CAS 北大核心 2024年第4期720-726,共7页
【目的】提出一种多任务自适应知识蒸馏的语音增强算法,旨在解决复杂模型在时间和硬件等计算成本方面带来的问题,同时提高语音增强算法的性能。【方法】首先,采用知识蒸馏的思想来解决现有的语音增强模型过于庞大、参数多造成计算成本... 【目的】提出一种多任务自适应知识蒸馏的语音增强算法,旨在解决复杂模型在时间和硬件等计算成本方面带来的问题,同时提高语音增强算法的性能。【方法】首先,采用知识蒸馏的思想来解决现有的语音增强模型过于庞大、参数多造成计算成本上升问题;其次,充分考虑不同时频单元之间的差异,引入加权因子来优化传统损失函数提升学生网络性能;为了避免教师网络预测的不确定性影响学生网络的性能,构建多任务自适应学习的知识蒸馏网络,可以更好地利用不同任务之间的关联性优化模型。【结果】实验仿真结果表明,所提出的算法在减少参数量、缩短计算时间的同时,还能有效提高语音增强模型的性能。 展开更多
关键词 语音增强 知识蒸馏 多任务自适应学习 加权损失函数
下载PDF
注意缺陷多动障碍两种亚型脑血流动力学特征研究
20
作者 华玖州 张洁 程芳 《宁波大学学报(理工版)》 2024年第1期77-83,共7页
探讨注意缺陷多动障碍(Attention Deficit and Hyperactive Disorder,ADHD)混合型(ADHD-C)及多动-冲动为主型(ADHD-HI)儿童在言语流畅性任务(Verbal Fluency Task,VFT)中脑血流动力学反应特征及差异.通过整合视听持续性操作测试将ADHD... 探讨注意缺陷多动障碍(Attention Deficit and Hyperactive Disorder,ADHD)混合型(ADHD-C)及多动-冲动为主型(ADHD-HI)儿童在言语流畅性任务(Verbal Fluency Task,VFT)中脑血流动力学反应特征及差异.通过整合视听持续性操作测试将ADHD患儿区分亚型(33名ADHD-C型及36名ADHD-HI型),之后采用功能近红外光谱成像仪技术(functional Near-Infrared Spectroscopy,fNIRS)测量两组患儿在VFT中前额和左右颞叶血流动力学反应特征,并计算其积分值与重心值.结果发现,在注意力商数上,ADHD-C组得分均低于ADHD-HI组,差异有统计学意义(P<0.05);两组亚型患儿视觉得分低于听觉得分,差异均有统计学意义(P<0.05).在VFT测试中,ADHD-C组的左右颞叶积分值较ADHD-HI组降低,差异有统计学意义(P<0.05);两组亚型患儿左右颞叶的积分值与综合注意商、听觉注意商、视觉注意商均呈显著正相关(P<0.01).由此可见,ADHD-C与ADHD-HI亚型在完成VFT时的脑左右颞叶的功能存在差异,且注意力受损越重,其血流动力学激活程度越低. 展开更多
关键词 注意力缺陷多动障碍 亚型 注意力特征 言语流畅性任务 功能近红外光谱成像仪技术
下载PDF
上一页 1 2 30 下一页 到第
使用帮助 返回顶部