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A divergent pattern in functional connectivity: a transdiagnostic perspective
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作者 Lu Zhang Lorenzo Pini 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第9期1885-1886,共2页
Functional magnetic resonance imaging(fMRI)is a popular tool used to investigate not only how the brain responds to specific stimuli during sensorimotor or cognitive tasks,but also brain activity at rest.The physics b... Functional magnetic resonance imaging(fMRI)is a popular tool used to investigate not only how the brain responds to specific stimuli during sensorimotor or cognitive tasks,but also brain activity at rest.The physics beyond this approach is based on the analysis of the blood oxygenation level-dependent signal. 展开更多
关键词 PATTERN connectivity FUNCTIONAL
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Research on Quantitative Identification of Three-Dimensional Connectivity of Fractured-Vuggy Reservoirs
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作者 Xingliang Deng Peng Cao +3 位作者 Yintao Zhang Yuhui Zhou Xiao Luo Liang Wang 《Energy Engineering》 EI 2024年第5期1195-1207,共13页
The fractured-vuggy carbonate oil resources in the western basin of China are extremely rich.The connectivity of carbonate reservoirs is complex,and there is still a lack of clear understanding of the development and ... The fractured-vuggy carbonate oil resources in the western basin of China are extremely rich.The connectivity of carbonate reservoirs is complex,and there is still a lack of clear understanding of the development and topological structure of the pore space in fractured-vuggy reservoirs.Thus,effective prediction of fractured-vuggy reservoirs is difficult.In view of this,this work employs adaptive point cloud technology to reproduce the shape and capture the characteristics of a fractured-vuggy reservoir.To identify the complex connectivity among pores,fractures,and vugs,a simplified one-dimensional connectivity model is established by using the meshless connection element method(CEM).Considering that different types of connection units have different flow characteristics,a sequential coupling calculation method that can efficiently calculate reservoir pressure and saturation is developed.By automatic history matching,the dynamic production data is fitted in real-time,and the characteristic parameters of the connection unit are inverted.Simulation results show that the three-dimensional connectivity model of the fractured-vuggy reservoir built in this work is as close as 90%of the fine grid model,while the dynamic simulation efficiency is much higher with good accuracy. 展开更多
关键词 Fractured-vuggy reservoir three-dimensional connectivity connection unit dynamic prediction automatic history matching
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Structural and functional connectivity of the whole brain and subnetworks in individuals with mild traumatic brain injury:predictors of patient prognosis
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作者 Sihong Huang Jungong Han +4 位作者 Hairong Zheng Mengjun Li Chuxin Huang Xiaoyan Kui Jun Liu 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第7期1553-1558,共6页
Patients with mild traumatic brain injury have a diverse clinical presentation,and the underlying pathophysiology remains poorly understood.Magnetic resonance imaging is a non-invasive technique that has been widely u... Patients with mild traumatic brain injury have a diverse clinical presentation,and the underlying pathophysiology remains poorly understood.Magnetic resonance imaging is a non-invasive technique that has been widely utilized to investigate neuro biological markers after mild traumatic brain injury.This approach has emerged as a promising tool for investigating the pathogenesis of mild traumatic brain injury.G raph theory is a quantitative method of analyzing complex networks that has been widely used to study changes in brain structure and function.However,most previous mild traumatic brain injury studies using graph theory have focused on specific populations,with limited exploration of simultaneous abnormalities in structural and functional connectivity.Given that mild traumatic brain injury is the most common type of traumatic brain injury encounte red in clinical practice,further investigation of the patient characteristics and evolution of structural and functional connectivity is critical.In the present study,we explored whether abnormal structural and functional connectivity in the acute phase could serve as indicators of longitudinal changes in imaging data and cognitive function in patients with mild traumatic brain injury.In this longitudinal study,we enrolled 46 patients with mild traumatic brain injury who were assessed within 2 wee ks of injury,as well as 36 healthy controls.Resting-state functional magnetic resonance imaging and diffusion-weighted imaging data were acquired for graph theoretical network analysis.In the acute phase,patients with mild traumatic brain injury demonstrated reduced structural connectivity in the dorsal attention network.More than 3 months of followup data revealed signs of recovery in structural and functional connectivity,as well as cognitive function,in 22 out of the 46 patients.Furthermore,better cognitive function was associated with more efficient networks.Finally,our data indicated that small-worldness in the acute stage could serve as a predictor of longitudinal changes in connectivity in patients with mild traumatic brain injury.These findings highlight the importance of integrating structural and functional connectivity in unde rstanding the occurrence and evolution of mild traumatic brain injury.Additionally,exploratory analysis based on subnetworks could serve a predictive function in the prognosis of patients with mild traumatic brain injury. 展开更多
关键词 cognitive function CROSS-SECTION FOLLOW-UP functional connectivity graph theory longitudinal study mild traumatic brain injury prediction small-worldness structural connectivity subnetworks whole brain network
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Joint Allocation of Computing and Connectivity Resources in Survivable Inter-Datacenter Elastic Optical Networks
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作者 Yang Tao Li Yang Chen Xue 《China Communications》 SCIE CSCD 2024年第8期172-181,共10页
Inter-datacenter elastic optical networks(EON)need to provide the service for the requests of cloud computing that require not only connectivity and computing resources but also network survivability.In this paper,to ... Inter-datacenter elastic optical networks(EON)need to provide the service for the requests of cloud computing that require not only connectivity and computing resources but also network survivability.In this paper,to realize joint allocation of computing and connectivity resources in survivable inter-datacenter EONs,a survivable routing,modulation level,spectrum,and computing resource allocation algorithm(SRMLSCRA)algorithm and three datacenter selection strategies,i.e.Computing Resource First(CRF),Shortest Path First(SPF)and Random Destination(RD),are proposed for different scenarios.Unicast and manycast are applied to the communication of computing requests,and the routing strategies are calculated respectively.Simulation results show that SRMLCRA-CRF can serve the largest amount of protected computing tasks,and the requested calculation blocking probability is reduced by 29.2%,28.3%and 30.5%compared with SRMLSCRA-SPF,SRMLSCRA-RD and the benchmark EPS-RMSA algorithms respectively.Therefore,it is more applicable to the networks with huge calculations.Besides,SRMLSCRA-SPF consumes the least spectrum,thereby exhibiting its suitability for scenarios where the amount of calculation is small and communication resources are scarce.The results demonstrate that the proposed methods realize the joint allocation of computing and connectivity resources,and could provide efficient protection for services under single-link failure and occupy less spectrum. 展开更多
关键词 computing and connectivity interdatacenter networks joint resource allocation service protection
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"Silk Road People-to-People Connectivity"Care for the Future Donation Ceremony Held in Nay Pyi Taw,Myanmar
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《International Understanding》 2024年第2期46-47,共2页
On April 1Oth,“Silk Road People-to-People Connectivity”Care for the Future Activity and a donation ceremony of school sports goods were held at China-Myanmar Friendship School,Basic Education High School(BEHS)No.14,... On April 1Oth,“Silk Road People-to-People Connectivity”Care for the Future Activity and a donation ceremony of school sports goods were held at China-Myanmar Friendship School,Basic Education High School(BEHS)No.14,in Nay Pyi Taw,Myanmar. 展开更多
关键词 ROAD Basic connectivity
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Dynamic interwell connectivity analysis of multi-layer waterflooding reservoirs based on an improved graph neural network
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作者 Zhao-Qin Huang Zhao-Xu Wang +4 位作者 Hui-Fang Hu Shi-Ming Zhang Yong-Xing Liang Qi Guo Jun Yao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1062-1080,共19页
The analysis of interwell connectivity plays an important role in the formulation of oilfield development plans and the description of residual oil distribution. In fact, sandstone reservoirs in China's onshore oi... The analysis of interwell connectivity plays an important role in the formulation of oilfield development plans and the description of residual oil distribution. In fact, sandstone reservoirs in China's onshore oilfields generally have the characteristics of thin and many layers, so multi-layer joint production is usually adopted. It remains a challenge to ensure the accuracy of splitting and dynamic connectivity in each layer of the injection-production wells with limited field data. The three-dimensional well pattern of multi-layer reservoir and the relationship between injection-production wells can be equivalent to a directional heterogeneous graph. In this paper, an improved graph neural network is proposed to construct an interacting process mimics the real interwell flow regularity. In detail, this method is used to split injection and production rates by combining permeability, porosity and effective thickness, and to invert the dynamic connectivity in each layer of the injection-production wells by attention mechanism.Based on the material balance and physical information, the overall connectivity from the injection wells,through the water injection layers to the production layers and the output of final production wells is established. Meanwhile, the change of well pattern caused by perforation, plugging and switching of wells at different times is achieved by updated graph structure in spatial and temporal ways. The effectiveness of the method is verified by a combination of reservoir numerical simulation examples and field example. The method corresponds to the actual situation of the reservoir, has wide adaptability and low cost, has good practical value, and provides a reference for adjusting the injection-production relationship of the reservoir and the development of the remaining oil. 展开更多
关键词 Graph neural network Dynamic interwell connectivity Production-injection splitting Attention mechanism Multi-layer reservoir
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The First Overseas Cooperation Station of Silk Road People-to-People Connectivity Unveiled in Budapest,Hungary
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《International Understanding》 2024年第2期44-45,共2页
On May 2nd,the Thematic Forum on China-Hungary Belt and Road Pragmatic Cooperation was held in Budapest,the capital of Hungary,during which,the China-Hungary Cooperation Station of Silk Road People-to-People Connectiv... On May 2nd,the Thematic Forum on China-Hungary Belt and Road Pragmatic Cooperation was held in Budapest,the capital of Hungary,during which,the China-Hungary Cooperation Station of Silk Road People-to-People Connectivity was officially launched.This is the first overseas station under the Action on Silk Road People-to-People Connectivity.It will surely provide important support to the achievement of more fruitful results in people-to-people exchanges and cooperation between the two countries. 展开更多
关键词 connectivity ROAD Budapest
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Soft connectivity of standards boosts high-quality Belt and Road development
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作者 Zhang Xiaoping 《China Standardization》 2024年第6期26-27,共2页
Shaanxi province serves as an important part in the Belt and Road cooperation,which is also at the forefront of China’s westward opening up.It also shoulders the significant missions of implementing national strategi... Shaanxi province serves as an important part in the Belt and Road cooperation,which is also at the forefront of China’s westward opening up.It also shoulders the significant missions of implementing national strategies including the ecological protection and high-quality development of the Yellow River Basin and the Western Region Development Strategy. 展开更多
关键词 boost ROAD connectivity
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"Silk Road People-to-People Connectivity"China-Cambodia Donation Activity Held in Phnom Penh
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《International Understanding》 2024年第2期48-49,共2页
On March 26th,the"Silk Road People-to-People Connectivity"China-Cambodia Donation Activity was held at Indradevi High School in Phnom Penh,Cambodia.Lv Xuejun,President and Chief Editor of the Contemporary Wo... On March 26th,the"Silk Road People-to-People Connectivity"China-Cambodia Donation Activity was held at Indradevi High School in Phnom Penh,Cambodia.Lv Xuejun,President and Chief Editor of the Contemporary World,Pay Sambo,Secretary General of Cambodia Civil Society Association Forum,Wu Chuanbing,Councilor of Chinese Embassy in Cambodia,Hu Jianguang,Deputy Director of the Education Committee of Haidian District of Beijing,Liu Zhanguo,Director of China Foundation for Peace and Development(CFPD)Cambodia Office,Soung Houth,President of National Union Alliance Chamber of Cambodia(NACC),Neak Sothea,President of Indradevi High School and other participants attended the event. 展开更多
关键词 connectivity DIRECTOR ROAD
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Brain mechanism of acupuncture for children with anisometropic amblyopia: a resting functional magnetic resonance imaging study based on voxel-mirrored homotopic connectivity
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作者 Jue Wang Jing Jia +4 位作者 Yan Sun Chong-Bing Ma Yu-Zhu Chen An-Guo Liu Xing-Ke Yan 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第2期339-347,共9页
AIM:To explore the brain mechanism of acupuncture for children with anisometropic amblyopia using the voxelmirror homotopic connectivity(VMHC)analysis method of resting functional magnetic resonance imaging(rs-fMRI)te... AIM:To explore the brain mechanism of acupuncture for children with anisometropic amblyopia using the voxelmirror homotopic connectivity(VMHC)analysis method of resting functional magnetic resonance imaging(rs-fMRI)technology based on clinical effectiveness.METHODS:Eighty children with anisometropic monocular amblyopia were randomly divided into two groups:control(40 cases,1 case of shedding)and acupuncture(40 cases,1 case of shedding)groups.The control group was treated with glasses,red flash,grating,and visual stimulations,with each procedure conducted for 5min per time.Based on routine treatment,the acupuncture group underwent acupuncture of“regulating qi and unblocking meridians to bright eyes”,Jingming(BL1),Cuanzhu(BL2),Guangming(GB37),Fengchi(GB20)acupoints were taken on both sides,with the needle kept for 30min each time.Both groups were treated once every other day,three times per week,for a total of 4wk.After the treatment,the overall curative effect of the two groups and the latency and amplitude changes of P100 wave of pattern visual-evoked potential were counted.At the same time,nine children with left eye amblyopia were randomly selected from the two groups and were scanned with rsfMRI before and after treatment.The differences in the brain regions between the two groups were compared and analyzed with VMHC.RESULTS:Chi-square test showed a notable difference in the total efficiency rate between the acupuncture(94.87%)and control groups(79.49%).Regarding the P100 wave latency and amplitude,the acupuncture group had significantly shorter latency and higher amplitude of P100 wave than the control group.Moreover,the VMHC values of the bilateral temporal lobe,superior temporal gyrus,and middle temporal gyrus were notably increased in the acupuncture group after treatment.CONCLUSION:Acupuncture combined with conventional treatment can significantly improve the corrected visual acuity and optic nerve conduction in children with anisometropic amblyopia.Compared with the conventional treatment,the regulation of acupuncture on the functional activities of the relevant brain areas in the anterior cerebellum may be an effective acupuncture mechanism for anisometropic amblyopia. 展开更多
关键词 resting functional magnetic resonance imaging voxel-mirror homotopy connection anisometropic amblyopia ACUPUNCTURE
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A Hybrid Level Set Optimization Design Method of Functionally Graded Cellular Structures Considering Connectivity
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作者 Yan Dong Kang Zhao +1 位作者 Liang Gao Hao Li 《Computers, Materials & Continua》 SCIE EI 2024年第4期1-18,共18页
With the continuous advancement in topology optimization and additive manufacturing(AM)technology,the capability to fabricate functionally graded materials and intricate cellular structures with spatially varying micr... With the continuous advancement in topology optimization and additive manufacturing(AM)technology,the capability to fabricate functionally graded materials and intricate cellular structures with spatially varying microstructures has grown significantly.However,a critical challenge is encountered in the design of these structures–the absence of robust interface connections between adjacent microstructures,potentially resulting in diminished efficiency or macroscopic failure.A Hybrid Level Set Method(HLSM)is proposed,specifically designed to enhance connectivity among non-uniform microstructures,contributing to the design of functionally graded cellular structures.The HLSM introduces a pioneering algorithm for effectively blending heterogeneous microstructure interfaces.Initially,an interpolation algorithm is presented to construct transition microstructures seamlessly connected on both sides.Subsequently,the algorithm enables the morphing of non-uniform unit cells to seamlessly adapt to interconnected adjacent microstructures.The method,seamlessly integrated into a multi-scale topology optimization framework using the level set method,exhibits its efficacy through numerical examples,showcasing its prowess in optimizing 2D and 3D functionally graded materials(FGM)and multi-scale topology optimization.In essence,the pressing issue of interface connections in complex structure design is not only addressed but also a robust methodology is introduced,substantiated by numerical evidence,advancing optimization capabilities in the realm of functionally graded materials and cellular structures. 展开更多
关键词 Hybrid level set method functionally graded cellular structure connectivity interpolated transition optimization design
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The Launching Ceremony of the Silk Road People-to-People Connectivity Donation Activity"Care for the Future"Held in Yangon
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《International Understanding》 2024年第1期37-38,共2页
The launching ceremony of the Silk Road Peopleto-People"Connectivity donation activity"Care for the Future was jointly held by China Foundation for Peace and Development and the Myanmar-Chinese Cooperation&a... The launching ceremony of the Silk Road Peopleto-People"Connectivity donation activity"Care for the Future was jointly held by China Foundation for Peace and Development and the Myanmar-Chinese Cooperation&Communication Centre in Yangon on January 16.The Yangjin Middle School in Yangon Province of Myanmar received football,volleyball,badminton,notebooks,LED lights and other school utensils and sporting goods. 展开更多
关键词 jointly connectivity ROAD
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Assessment of sediment connectivity using modelling and field-based approaches in the Slavíč River catchment(MoravskoslezskéBeskydy Mts,Czech Republic)
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作者 MACUROVÁ Tereza ŠKARPICH Václav 《Journal of Mountain Science》 SCIE CSCD 2024年第3期734-753,共20页
Mountain streams act as conveyors of sediments within the river continuum,where the physical transport of sediments between river reaches through the catchment or between individual parts(e.g.,between hillslopes and c... Mountain streams act as conveyors of sediments within the river continuum,where the physical transport of sediments between river reaches through the catchment or between individual parts(e.g.,between hillslopes and channels)of the catchment is assumed.This study focused on sediment connectivity analysis in the SlavíčRiver catchment in the MoravskoslezskéBeskydy Mts in the eastern part of the Czech Republic.The connectivity index and connectivity index target modelling were combined with an analysis of anthropogenic interventions.Additionally,field mapping,grain size of bed sediments and stream power analysis were used to obtain information about connectivity in the catchment.Based on the analysis and obtained results,terrain topography is the current main driving factor affecting the connectivity of sediment movement in the SlavíčRiver catchment.However,the modelling provided valuable information about high sediment connectivity despite different recent land use conditions(highly forested area of the catchment)than those in historical times from the 16th to 19th centuries when the SlavíčRiver catchment was highly deforested and sediment connectivity was probably higher.The analysis of anthropogenic interventions,field mapping,grain size of bed sediments and stream power analysis revealed more deceleration of sediment movement through the catchment,decreased sediment connectivity with bed erosion,and gradual river channel process transformation in some reaches.Field mapping has identified various natural formations and human-induced changes impacting the longitudinal and lateral connectivity in the SlavíčRiver.For instance,embankments along 48%of the river's length,both on the right and left banks,significantly hinder lateral sediment supply to the channel.Stream power index analysis indicates increased energy levels in the flowing water in the river's upper reaches(up to 404.8 W m^(-2)).This high energy is also observed in certain downstream sections(up to 337.6 W m^(-2)),where it is influenced by human activities.These conditions lead to intensified erosion processes,playing a crucial role in sediment connectivity.Similar observations were described in recent studies that pointed out the long-term human interventions on many streams draining European mountains,where a decrease in sediment connectivity in these streams is linked with sediment deficits and the transformation of processes forming channels. 展开更多
关键词 Mountain stream connectivity analysis MODELLING Grain size analysis SlavíčRiver MoravskoslezskéBeskydy Mts
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"Silk Road People-to-People Connectivity"China-Myanmar Friendly Cultural and Educational Exchanges Held inYangon
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《International Understanding》 2024年第1期35-36,共2页
On January 1Oth,at the invitation of the Yangon University of Foreign Languages for its Cultural Exchanges Week,the China Foundation for Peace and Development and the Myanmar Chinese Cooperation&Communication Cent... On January 1Oth,at the invitation of the Yangon University of Foreign Languages for its Cultural Exchanges Week,the China Foundation for Peace and Development and the Myanmar Chinese Cooperation&Communication Centre,jointly organised the"Silk Road People-to-People Connectivity"China-Myanmar Friendly Cultural and Educational Exchange activity.U Soe Thein,Chief Minister of Yangon Province,Zaw Myint,Deputy Minister of Education of Myanmar,and Kyi Shwin,President of Yangon University of Foreign Languages,attended the activity and delivered speeches. 展开更多
关键词 jointly connectivity Myanmar
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Research on the prediction method for fluvial-phase sandbody connectivity based on big data analysis--a case study of Bohai a oilfield
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作者 Cai Li Fei Ma +1 位作者 Yuxiu Wang Delong Zhang 《Artificial Intelligence in Geosciences》 2024年第1期359-366,共8页
The connectivity of sandbodies is a key constraint to the exploration effectiveness of Bohai A Oilfield.Conventional connectivity studies often use methods such as seismic attribute fusion,while the development of con... The connectivity of sandbodies is a key constraint to the exploration effectiveness of Bohai A Oilfield.Conventional connectivity studies often use methods such as seismic attribute fusion,while the development of contiguous composite sandbodies in this area makes it challenging to characterize connectivity changes with conventional seismic attributes.Aiming at the above problem in the Bohai A Oilfield,this study proposes a big data analysis method based on the Deep Forest algorithm to predict the sandbody connectivity.Firstly,by compiling the abundant exploration and development sandbodies data in the study area,typical sandbodies with reliable connectivity were selected.Then,sensitive seismic attribute were extracted to obtain training samples.Finally,based on the Deep Forest algorithm,mapping model between attribute combinations and sandbody connectivity was established through machine learning.This method achieves the first quantitative determination of the connectivity for continuous composite sandbodies in the Bohai Oilfield.Compared with conventional connectivity discrimination methods such as high-resolution processing and seismic attribute analysis,this method can combine the sandbody characteristics of the study area in the process of machine learning,and jointly judge connectivity by combining multiple seismic attributes.The study results show that this method has high accuracy and timeliness in predicting connectivity for continuous composite sandbodies.Applied to the Bohai A Oilfield,it successfully identified multiple sandbody connectivity relationships and provided strong support for the subsequent exploration potential assessment and well placement optimization.This method also provides a new idea and method for studying sandbody connectivity under similar complex geological conditions. 展开更多
关键词 Continuous sandbody connectivity prediction Big data analysis Deep forest Machine learning
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Connectivity map技术在中药研究中的应用 被引量:7
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作者 张晓芳 康永波 +1 位作者 苏君鸿 孔祥阳 《浙江大学学报(农业与生命科学版)》 CAS CSCD 北大核心 2016年第5期543-550,共8页
Connectivity map(CMap)是基于RNA芯片研究药物作用机制和药物重定位的技术与数据资源,主要的优势在于能够高效地对全基因组上的基因表达做整体分析。相对于低通量的药理学、毒理学方法以及色谱技术,该技术能以全面、高通量、准确等优... Connectivity map(CMap)是基于RNA芯片研究药物作用机制和药物重定位的技术与数据资源,主要的优势在于能够高效地对全基因组上的基因表达做整体分析。相对于低通量的药理学、毒理学方法以及色谱技术,该技术能以全面、高通量、准确等优点广泛应用于药物研究。尤其对由多种化合物共同作用发挥疗效的中药,CMap技术可以突破"药物-靶标"测定技术的单一性困难,对中药的作用机制做综合性分析,从分子水平上阐明中药的药物作用机制,有利于开发自主知识产权的中药,也为中药获取国际认可奠定理论基础。本文系统介绍CMap技术在中药研究方面的应用潜力,同时对该技术研究中药的作用机制、药物重定位及鉴别有效成分进行评价,还对推动中药走向国际市场做了具体分析与展望。 展开更多
关键词 connectivity MAP技术 中药 作用机制 药物重定位 有效成分
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ON THE EXISTENCE OF THE h-RESTRICTED EDGE CONNECTIVITY OF A GRAPH 被引量:2
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作者 王应前 李乔 《Journal of Shanghai Jiaotong university(Science)》 EI 2001年第2期131-133,共3页
Let h be a nonnegative integer. The h-restricted edge connectivity λ h(G) of a simple connected graph G is defined as the minimum cardinality over the sets of edges of G, if any, whose removal disconnects G and every... Let h be a nonnegative integer. The h-restricted edge connectivity λ h(G) of a simple connected graph G is defined as the minimum cardinality over the sets of edges of G, if any, whose removal disconnects G and every component of the resulting graph has more than h vertices. This paper gave a necessary and sufficient condition and also three useful sufficient conditions to guarantee the existence of λ h(G). Moreover, it explicitly characterized the graphs whose 2-restricted edge connectivities do not exist. 展开更多
关键词 h-restricted EDGE connectivity GRAPH
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Calculation connectivity reliability of road networks based on recursive decomposition arithmetic 被引量:2
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作者 潘艳荣 邓卫 《Journal of Southeast University(English Edition)》 EI CAS 2008年第1期85-89,共5页
In order to decrease the calculation complexity of connectivity reliability of road networks, an improved recursive decomposition arithmetic is proposed. First, the basic theory of recursive decomposition arithmetic i... In order to decrease the calculation complexity of connectivity reliability of road networks, an improved recursive decomposition arithmetic is proposed. First, the basic theory of recursive decomposition arithmetic is reviewed. Then the characteristics of road networks, which are different from general networks, are analyzed. Under this condition, an improved recursive decomposition arithmetic is put forward which fits road networks better. Furthermore, detailed calculation steps are presented which are convenient for the computer, and the advantage of the approximate arithmetic is analyzed based on this improved arithmetic. This improved recursive decomposition arithmetic directly produces disjoint minipaths and avoids the non-polynomial increasing problems. And because the characteristics of road networks are considered, this arithmetic is greatly simplified. Finally, an example is given to prove its validity. 展开更多
关键词 recursive decomposition arithmetic road network connectivity reliability disjoint minipath topological structure
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Spatial connectivity and distribution of landscape type in the natural secondary forests of eastern mountainous region,northeast China——a case study of Mao'ershan region in Heilongjiang Province
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作者 李淑娟 隋玉正 +2 位作者 冯海清 王凤友 李玉文 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第2期141-144,i003,共5页
Mao'ershan region is representative in the natural secondary forested region of the eastern mountainous region, northeast China. The landscape nearest neighbor index and landscape connectivity index were calculate... Mao'ershan region is representative in the natural secondary forested region of the eastern mountainous region, northeast China. The landscape nearest neighbor index and landscape connectivity index were calculated with ARC/INFO software for Mao'ershan region. The spatial distribution of the landscape of the region was analyzed. The results showed that the landscape connectivity index of non-woodland was significantly higher than that of woodland. The landscape connectivity index of natural forest was nearly equal to zero, which means its fragmentation degree is high. The nearest neighbor index of plantation was lower than that of natural forest and non-forestland. Among the man-made forests, the distance index of the coniferous mixed plantation is the lowest, and its pattern is nearly glomeration. The landscape pattern of natural forest presented nearly random distribution. Among non-forest land, the distance index of cut blank was the lowest, and its pattern was also nearly glomeration. Keywords Landscape type - Landscape pattern - Nearest neighbor index - Landscape connectivity index - Natural secondary forest - Northeast China CLC number S759.92 Document code A Foundation item: This paper was supported by the Key Project of State Department of Science Technology (2002BA515B040).Biography: LI SHu-juan (1977), female. Lecture in Ocean University of China, Qingdao 266003, P. R. China.Responsible editor: Zhu Hong 展开更多
关键词 Landscape type Landscape pattern Nearest neighbor index Landscape connectivity index Natural secondary forest Northeast China
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Improved approach to enhanced Internet connectivity for mobile ad hoc networks
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作者 沈斌 李波 石冰心 《Journal of Southeast University(English Edition)》 EI CAS 2007年第1期16-21,共6页
An improved internetworking approach is proposed to enhance the Internet connectivity which is deteriorated due to unidirectional links and blind rebroadcasting of gateway discovery packets for mobile ad hoc networks.... An improved internetworking approach is proposed to enhance the Internet connectivity which is deteriorated due to unidirectional links and blind rebroadcasting of gateway discovery packets for mobile ad hoc networks. The hybrid gateway discovery scheme that combined the advantages of a proactive and reactive gateway discovery approach is used to achieve high connectivity while keeping overhead costs low. By exchanging ad hoc on-demand distance vector (AODV) hello packet which includes additional fields named symmetric neighbor list and asymmetric neighbor list, unidirectional links are removed from route computation and broadcast storm can also be relieved simultaneously. Performance results using ns-2 simulations, under varying numbers of unidirectional links and node speeds, show that this improved Internet connectivity approach can provide better performance than others. 展开更多
关键词 mobile ad hoc networks Internet connectivity gateway discovery unidirectional link broadcast storm
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