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Endoscopic and laparoscopic treatment of ileocecal laterally spreading tumor with concomitant appendiceal adenoma:A case report and review of literature
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作者 Ying-Hui Huang Li Ma +6 位作者 Bin Cao Yue-Juan Zhang Qun Gao Zhen-Ming Zhu Xiao-Lu Qiao Lei Wang Bao-Guo He 《World Journal of Gastrointestinal Surgery》 2025年第9期448-454,共7页
BACKGROUND Ileocecal laterally spreading tumors(LSTs)complicated by appendiceal tubular adenoma are rare and challenging to diagnose because of the absence of typical symptoms and specific diagnostic signs.Traditional... BACKGROUND Ileocecal laterally spreading tumors(LSTs)complicated by appendiceal tubular adenoma are rare and challenging to diagnose because of the absence of typical symptoms and specific diagnostic signs.Traditionally,the primary treatment has been laparoscopic appendectomy(LA).CASE SUMMARY A 63-year-old female presented with changes in bowel habits.Colonoscopy revealed an ileocecal LST.The patient underwent endoscopic submucosal dissection.Postoperative follow-up colonoscopy revealed mucosal elevation at the appendiceal orifice,with pathology confirming tubular adenoma.Abdominal computed tomography indicated a suspicious appendiceal tumor,leading to LA with partial cecectomy.The postoperative recovery was uneventful.At the 1-year follow-up,colonoscopy revealed no evidence of tumor recurrence.CONCLUSION Ileocecal LSTs with appendiceal tubular adenomas are traditionally treated with LA.endoscopic submucosal dissection can also yield favorable outcomes. 展开更多
关键词 Appendiceal tubular adenoma Ileocecal laterally spreading tumor Appendiceal laterally spreading tumor Endoscopic submucosal dissection Laparoscopic appendectomy Case report
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Impact of message fatigue and individual behavioral responses on epidemiological spread in temporal simplicial networks 被引量:1
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作者 Xiao-Nan Fan Xuemei You 《Chinese Physics B》 2025年第3期32-43,共12页
Health information spreads rapidly,which can effectively control epidemics.However,the swift dissemination of information also has potential negative impacts,which increasingly attracts attention.Message fatigue refer... Health information spreads rapidly,which can effectively control epidemics.However,the swift dissemination of information also has potential negative impacts,which increasingly attracts attention.Message fatigue refers to the psychological response characterized by feelings of boredom and anxiety that occur after receiving an excessive amount of similar information.This phenomenon can alter individual behaviors related to epidemic prevention.Additionally,recent studies indicate that pairwise interactions alone are insufficient to describe complex social transmission processes,and higher-order structures representing group interactions are crucial.To address this,we develop a novel epidemic model that investigates the interactions between information,behavioral responses,and epidemics.Our model incorporates the impact of message fatigue on the entire transmission system.The information layer is modeled using a static simplicial network to capture group interactions,while the disease layer uses a time-varying network based on activity-driven model with attractiveness to represent the self-protection behaviors of susceptible individuals and self-isolation behaviors of infected individuals.We theoretically describe the co-evolution equations using the microscopic Markov chain approach(MMCA)and get the epidemic threshold.Experimental results show that while the negative impact of message fatigue on epidemic transmission is limited,it significantly weakens the group interactions depicted by higher-order structures.Individual behavioral responses strongly inhibit the epidemic.Our simulations using the Monte Carlo(MC)method demonstrate that greater intensity in these responses leads to clustering of susceptible individuals in the disease layer.Finally,we apply the proposed model to real networks to verify its reliability.In summary,our research results enhance the understanding of the information-epidemic coupling dynamics,and we expect to provide valuable guidance for managing future emerging epidemics. 展开更多
关键词 Monte Carlo simulation microscopic Markov chain approach message fatigue information-epidemic coupled spreading simplicial complex
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Modeling the spread risk of dengue vector Aedes albopictus caused by environmental factors in Shanghai China
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作者 Jiamin Wang Yanfeng Gong +7 位作者 Junhui Huang Ning Xu Yu Zhou Liyun Zhu Liang Shi Yue Chen Qingwu Jiang Yibiao Zhou 《Asian Pacific Journal of Tropical Medicine》 2025年第6期261-268,共8页
Objective:To predict the distribution of dengue vector Aedes(Ae.)albopictus and identify high-risk areas for dengue fever transmission.Methods:Data on Ae.albopictus occurrences were collected from electronic databases... Objective:To predict the distribution of dengue vector Aedes(Ae.)albopictus and identify high-risk areas for dengue fever transmission.Methods:Data on Ae.albopictus occurrences were collected from electronic databases.Ensemble models were developed to assess the impacts of climate,vegetation,and human activity on Ae.albopictus.The optimal ensemble model was then used to identify the distribution of suitable areas for Ae.albopictus.Results:After removing duplicate sites and retaining only one location per 100 m×100 m grid,189 Ae.albopictus breeding sites were identified.The optimal ensemble model revealed that Ae.albopictus exhibited higher breeding suitability in Shanghai under specific conditions:a normalized difference vegetation index of 0.1 to 0.6,maximum precipitation in the warmest month ranging from 400 mm to 470 mm,maximum temperature in the warmest month between 30.0℃and 31.0℃,and proximity to waterways within 0.5 km.The most suitable habitats for Ae.albopictus were primarily concentrated in Shanghai’s central urban areas and scattered across the inner suburban districts.Conclusions:The high-risk areas of Ae.albopictus are widely distributed throughout the central urban area and scattered across the inner suburban district of Shanghai,creating conditions conducive to the outbreak of dengue fever.It is essential to enhance targeted control measures for Ae.albopictus in the identified risk areas. 展开更多
关键词 DENGUE spread risk Prediction METROPOLITAN Aedes albopictus
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Influence of negative information dissemination and vaccination behavioral decision-making on epidemic spreading in a three-layer network
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作者 Liang'an Huo Leyao Yin 《Chinese Physics B》 2025年第6期667-681,共15页
Information plays a crucial role in guiding behavioral decisions during public health emergencies. Individuals communicate to acquire relevant knowledge about an epidemic, which influences their decisions to adopt pro... Information plays a crucial role in guiding behavioral decisions during public health emergencies. Individuals communicate to acquire relevant knowledge about an epidemic, which influences their decisions to adopt protective measures.However, whether to disseminate specific information is also a behavioral decision. In light of this understanding, we develop a coupled information–vaccination–epidemic model to depict these co-evolutionary dynamics in a three-layer network. Negative information dissemination and vaccination are treated as separate decision-making processes. We then examine the combined effects of herd and risk motives on information dissemination and vaccination decisions through the lens of game theory. The microscopic Markov chain approach(MMCA) is used to describe the dynamic process and to derive the epidemic threshold. Simulation results indicate that increasing the cost of negative information dissemination and providing timely clarification can effectively control the epidemic. Furthermore, a phenomenon of diminishing marginal utility is observed as the cost of dissemination increases, suggesting that authorities do not need to overinvest in suppressing negative information. Conversely, reducing the cost of vaccination and increasing vaccine efficacy emerge as more effective strategies for outbreak control. In addition, we find that the scale of the epidemic is greater when the herd motive dominates behavioral decision-making. In conclusion, this study provides a new perspective for understanding the complexity of epidemic spreading by starting with the construction of different behavioral decisions. 展开更多
关键词 negative information VACCINATION epidemic spreading behavioral decision-making three-layer network
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A stacking-based model for the spread of Botryosphaeria laricina
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作者 Hongwei Zhou Shibo Zhang +3 位作者 Meng Xie Xiaodong Li Yifan Chen Wenhao Dai 《Journal of Forestry Research》 2025年第1期427-443,共17页
Botryosphaeria laricina(larch shoot blight)was first identified in 1973 in Jilin Province,China.The disease spread rapidly and caused considerable damage because its pathogenesis was unknown at the time and there were... Botryosphaeria laricina(larch shoot blight)was first identified in 1973 in Jilin Province,China.The disease spread rapidly and caused considerable damage because its pathogenesis was unknown at the time and there were no effective controls or quarantine methods.At present,it shows a spreading trend,but most research can only conduct physiological analyses within a relatively short period,combining individual influencing factors.Nevertheless,methods such as neural network models,ensemble learning algorithms,and Markov models are used in pest and disease prediction and forecasting.However,there may be fitting issues or inherent limitations associated with these methods.This study obtained B.laricina data at the county level from 2003 to 2021.The dataset was augmented using the SMOTE algorithm,and then algorithms such as XGBoost were used to select the significant features from a combined set of 12 features.A new stacking fusion model has been proposed to predict the status of B.laricina.The model is based on random forest,gradient boosted decision tree,CatBoost and logistic regression algorithms.The accuracy,recall,specificity,precision,F_(1) value and AUC of the model reached 90.9%,91.6%,90.4%,88.8%,90.2%and 96.2%.The results provide evidence of the strong performance and stability of the model.B.laricina is mainly found in the northeast and this study indicates that it is spreading northwest.Reasonable means should be used promptly to prevent further damage and spread. 展开更多
关键词 Botryosphaeria laricina Data augmentation Feature selection STACKING Status of spread
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Trending and emerging prospects of physics-based and ML-based wildfire spread models:a comprehensive review
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作者 Harikesh Singh Li‑Minn Ang +4 位作者 Tom Lewis Dipak Paudyal Mauricio Acuna Prashant Kumar Srivastava Sanjeev Kumar Srivastava 《Journal of Forestry Research》 2025年第1期27-59,共33页
The significant threat of wildfires to forest ecology and biodiversity,particularly in tropical and subtropical regions,underscores the necessity for advanced predictive models amidst shifting climate patterns.There i... The significant threat of wildfires to forest ecology and biodiversity,particularly in tropical and subtropical regions,underscores the necessity for advanced predictive models amidst shifting climate patterns.There is a need to evaluate and enhance wildfire prediction methods,focusing on their application during extended periods of intense heat and drought.This study reviews various wildfire modelling approaches,including traditional physical,semi-empirical,numerical,and emerging machine learning(ML)-based models.We critically assess these models’capabilities in predicting fire susceptibility and post-ignition spread,highlighting their strengths and limitations.Our findings indicate that while traditional models provide foundational insights,they often fall short in dynamically estimating parameters and predicting ignition events.Cellular automata models,despite their potential,face challenges in data integration and computational demands.Conversely,ML models demonstrate superior efficiency and accuracy by leveraging diverse datasets,though they encounter interpretability issues.This review recommends hybrid modelling approaches that integrate multiple methods to harness their combined strengths.By incorporating data assimilation techniques with dynamic forecasting models,the predictive capabilities of ML-based predictions can be significantly enhanced.This review underscores the necessity for continued refinement of these models to ensure their reliability in real-world applications,ultimately contributing to more effective wildfire mitigation and management strategies.Future research should focus on improving hybrid models and exploring new data integration methods to advance predictive capabilities. 展开更多
关键词 Wildfire spread Fire prediction models Cellular automata model WRF-Fire/SFire FIRETEC CAWFE WFDS
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Explosive information spreading in higher-order networks:Effect of social reinforcement
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作者 Yu Zhou Yingpeng Liu +4 位作者 Liang Yuan Youhao Zhuo Kesheng Xu Jiao Wu Muhua Zheng 《Chinese Physics B》 2025年第3期196-202,共7页
Information spreading has been investigated for many years,but the mechanism of why the information explosively catches on overnight is still under debate.This explosive spreading phenomenon was usually considered dri... Information spreading has been investigated for many years,but the mechanism of why the information explosively catches on overnight is still under debate.This explosive spreading phenomenon was usually considered driven separately by social reinforcement or higher-order interactions.However,due to the limitations of empirical data and theoretical analysis,how the higher-order network structure affects the explosive information spreading under the role of social reinforcement has not been fully explored.In this work,we propose an information-spreading model by considering the social reinforcement in real and synthetic higher-order networks,describable as hypergraphs.Depending on the average group size(hyperedge cardinality)and node membership(hyperdegree),we observe two different spreading behaviors:(i)The spreading progress is not sensitive to social reinforcement,resulting in the information localized in a small part of nodes;(ii)a strong social reinforcement will promote the large-scale spread of information and induce an explosive transition.Moreover,a large average group size and membership would be beneficial to the appearance of the explosive transition.Further,we display that the heterogeneity of the node membership and group size distributions benefit the information spreading.Finally,we extend the group-based approximate master equations to verify the simulation results.Our findings may help us to comprehend the rapidly information-spreading phenomenon in modern society. 展开更多
关键词 explosive information spreading social reinforcement higher-order interactions complex network
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Endoscopic resection of colorectal laterally spreading tumors:Clinicopathologic characteristics and risk factors for treatment outcomes
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作者 Li-Hua Guo Ke-Feng Hu +3 位作者 Min Miao Yong Ding Xin-Jun Zhang Guo-Liang Ye 《World Journal of Gastrointestinal Endoscopy》 2025年第6期85-98,共14页
BACKGROUND Colorectal laterally spreading tumors(LSTs)are best treated with endoscopic submucosal dissection or endoscopic mucosal resection.AIM To analyze the clinicopathological and endoscopic profiles of colorectal... BACKGROUND Colorectal laterally spreading tumors(LSTs)are best treated with endoscopic submucosal dissection or endoscopic mucosal resection.AIM To analyze the clinicopathological and endoscopic profiles of colorectal LSTs,determine predictive factors for high-grade dysplasia(HGD)/carcinoma(CA),submucosal invasion,and complications.METHODS We retrospectively assessed the endoscopic and histological characteristics of 375 colorectal LSTs at our hospital between January 2016 and December 2023.We performed univariate and multivariate analysis to identify risk factors associated with HGD/CA,submucosal invasion and complications.RESULTS The numbers of granular(LST-G)and non-granular LST(LST-NG)were 260 and 115,respectively.The rates of low-grade dysplasia and HGD/CA were 60.3%and 39.7%,respectively.Multivariate analysis indicated that a tumor size≥30 mm[odds ratio(OR)=1.934,P=0.032],LST granular nodular mixed type(OR=2.100,P=0.005),and LST non-granular pseudo depressed type(NG-PD)(OR=3.016,P=0.015)were independent risk factors significantly associated with higher odds of HGD/CA.NG-PD(OR=6.506,P=0.001),tumor size(20-29 mm)(OR=2.631,P=0.036)and tumor size≥30 mm(OR=3.449,P=0.016)were associated with increased odds of submucosal invasion.Tumor size≥30 mm(OR=4.888,P=0.003)was a particularly important predictor of complications.A nomogram model demonstrated a satisfactory fit,with an area under the receiver operating characteristic curve of 0.716(95%confidence interval:0.653-0.780),indicating strong predictive performance.CONCLUSION The novel nomogram incorporating tumor size,location,and morphology predicted HGD/CA during endoscopic resection for LSTs.NG-PD lesions larger than 20 mm were more likely to invade the submucosa.Tumor size≥30 mm was an important predictor of complications. 展开更多
关键词 Colorectal neoplasms Laterally spreading tumor Endoscopic morphology Endoscopic submucosal dissection Endoscopic mucosal resection Submucosal invasion
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Activation of peroxymonosulfate by sustainable biomass-based carbon nanotubes for controlling the spread of plant viruses in water environments
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作者 Jian Tang Yujie Wang +2 位作者 JunMa Yujie Chen Ming Chen 《Journal of Environmental Sciences》 2025年第3期99-112,共14页
With the increasing demand for water in hydroponic systems and agricultural irrigation,viral diseases have seriously affected the yield and quality of crops.By removing plant viruses in water environments,virus transm... With the increasing demand for water in hydroponic systems and agricultural irrigation,viral diseases have seriously affected the yield and quality of crops.By removing plant viruses in water environments,virus transmission can be prevented and agricultural production and ecosystems can be protected.But so far,there have been few reports on the removal of plant viruses in water environments.Herein,in this study,easily recyclable biomass-based carbon nanotubes catalysts were synthesized with varying metal activities to activate peroxymonosulfate(PMS).Among them,the magnetic 0.125Fe@NCNTs-1/PMS system showed the best overall removal performance against pepper mild mottle virus,with a 5.9 log_(10)removal within 1 min.Notably,the key reactive species in the 0.125Fe@NCNTs-1/PMS system is^(1)O_(2),which can maintain good removal effect in real water matrices(river water and tap water).Through RNA fragment analyses and label free analysis,it was found that this system could effectively cleave virus particles,destroy viral proteins and expose their genome.The capsid protein of pepper mild mottle virus was effectively decomposed where serine may be the main attacking sites by^(1)O_(2).Long viral RNA fragments(3349 and 1642 nt)were cut into smaller fragments(∼160 nt)and caused their degradation.In summary,this study contributes to controlling the spread of plant viruses in real water environment,which will potentially help protect agricultural production and food safety,and improve the health and sustainability of ecosystems. 展开更多
关键词 Pepper mild mottle virus Removal Plant virus spread Biomass-based carbon nanotubes Water environments
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SPREADING SPEED FOR A TIME-SPACE PERIODIC EPIDEMIC MODEL IN DISCRETE MEDIA
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作者 Haiqin ZHAO 《Acta Mathematica Scientia》 2025年第3期1005-1018,共14页
This paper is devoted to investigating the spreading speed of a time-space periodic epidemic model with vital dynamics and standard incidence in discrete media. We establish the existence of the leftward and rightward... This paper is devoted to investigating the spreading speed of a time-space periodic epidemic model with vital dynamics and standard incidence in discrete media. We establish the existence of the leftward and rightward spreading speeds for the infective individuals, which can be used to estimate how fast the disease spreads. To overcome the difficulty arising from the lack of comparison principle for such time-space periodic nonmonotone systems, our proof is mainly based on constructing a series of scalar time-space periodic equations, establishing the spreading speeds for such auxiliary equations and using comparison methods. It may be the first work to study the spreading speed for time-space periodic non-monotone systems. 展开更多
关键词 spreading speed epidemic models time-space periodic habitats
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双圈图的Laplace spread 被引量:1
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作者 李平 施劲松 李瑞林 《华东师范大学学报(自然科学版)》 CAS CSCD 北大核心 2010年第1期6-9,共4页
图的Laplace spread定义为图的最大Laplace特征值与次小Laplace特征值之差.利用多项式函数的性质,得到了具有最大Laplace spread的双圈图.
关键词 LAPLACE特征值 双圈图 LAPLACE spread
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中性风在中低纬Spread-F中的作用 被引量:4
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作者 谢红 刘滨莎 萧佐 《北京大学学报(自然科学版)》 CAS CSCD 北大核心 1996年第1期78-88,共11页
讨论了中低纬度电离层F区中有碰撞的Rayleigh-Taylor不稳定性的线性增长率,着重考察背景中性风对增长率的影响,首先建立了适合于描述中低纬地区R-T不稳定性的基本方程,其中包括背景中性风和电场。在此基础上导出了色散关系和不稳定性增... 讨论了中低纬度电离层F区中有碰撞的Rayleigh-Taylor不稳定性的线性增长率,着重考察背景中性风对增长率的影响,首先建立了适合于描述中低纬地区R-T不稳定性的基本方程,其中包括背景中性风和电场。在此基础上导出了色散关系和不稳定性增长率γ。结果表明,γ随纬度增加而逐渐减小,虽然东西方向和垂直向下的中性风分量有利于不稳定性增长,但在比30度更高的纬度,正常的背景中性风很难使γ为正值,除非存在合适的东西方向电场,亦即电场在中纬度Spread F的形成方面起着重要的作用。文中还根据比较合乎实际的电离层电子密度分布模式估算了线性增长率γ的季节变化。 展开更多
关键词 中纬扩展F 中性风 电离层 R-T不稳定性 spread-F
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双圈图的Laplacian Spread(英文) 被引量:1
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作者 刘颖 王立庆 《数学进展》 CSCD 北大核心 2011年第6期759-764,共6页
Laplacian spread的概念在刻画图的整体性质方面非常重要.近年来,Fan等分别刻画了树中具有极大和极小Laplacian spread的图.另外Bao等确定了在所有单圈图中具有极大Laplacian spread的图.边数减去顶点数目为1的连通图称为双圈图.令B_n... Laplacian spread的概念在刻画图的整体性质方面非常重要.近年来,Fan等分别刻画了树中具有极大和极小Laplacian spread的图.另外Bao等确定了在所有单圈图中具有极大Laplacian spread的图.边数减去顶点数目为1的连通图称为双圈图.令B_n是所有有n个顶点构成的双圈图集合.对n≥11,本文确定了B_n中所有具有极大Laplacian spread的那些图. 展开更多
关键词 双圈图 LAPLACIAN spread LAPLACIAN特征值
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声重波激发的赤道Spread—F的拓扑特性研究 被引量:1
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作者 谢红 萧佐 王宪民 《空间科学学报》 CAS CSCD 北大核心 1997年第4期309-316,共8页
本文对声重波激发的Spread-F扰动的非线性制约方程的拓扑特性进行了定性讨论和数值计算.研究了Spread-F的混沌特征及参数范围.结果表明声重波在不同条件时对Spread-F的激发作用有本质的不同.
关键词 spread-F 声重波 混沌 拓扑 赤道 电离层
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Spread-F的经度效应 被引量:2
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作者 张天华 肖佐 《北京大学学报(自然科学版)》 CAS CSCD 北大核心 2001年第3期348-352,共5页
从三维地理坐标系出发建立模型 ,考虑了地磁倾角和偏角的影响 ,研究Spread F现象的全球分布特点 ,是对以前的研究从赤道地区向中、低纬度地区的推广。从该三维模型中可以看到地磁场的大小和位型的影响 (包括磁倾角和磁偏角的效应 )。由... 从三维地理坐标系出发建立模型 ,考虑了地磁倾角和偏角的影响 ,研究Spread F现象的全球分布特点 ,是对以前的研究从赤道地区向中、低纬度地区的推广。从该三维模型中可以看到地磁场的大小和位型的影响 (包括磁倾角和磁偏角的效应 )。由于地磁位型的不同 ,发生率的分布并不具有经度对称性 ,即使在磁赤道附近也如此。在某些特殊的经度和纬度地区 ,会达到发生率的峰值。 展开更多
关键词 spread-F 三维地理坐标系 经度效应 地磁效应 电离层风
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Fast method for spreading sequence estimation of DSSS signal based on maximum likelihood function 被引量:11
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作者 Yanhua Peng Bin Tang Ming Lv 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第6期948-953,共6页
To estimate the spreading sequence of the direct sequence spread spectrum (DSSS) signal, a fast algorithm based on maximum likelihood function is proposed, and the theoretical derivation of the algorithm is provided. ... To estimate the spreading sequence of the direct sequence spread spectrum (DSSS) signal, a fast algorithm based on maximum likelihood function is proposed, and the theoretical derivation of the algorithm is provided. By simplifying the objective function of maximum likelihood estimation, the algorithm can realize sequence synchronization and sequence estimation via adaptive iteration and sliding window. Since it avoids the correlation matrix computation, the algorithm significantly reduces the storage requirement and the computation complexity. Simulations show that it is a fast convergent algorithm, and can perform well in low signal to noise ratio (SNR). 展开更多
关键词 direct sequence spread spectrum (DSSS) signal spreading sequence maximum likelihood estimation (MLE).
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基于Spread业务支撑系统的拓扑构造
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作者 董立岩 殷涵 +2 位作者 王利民 毛锐 黄乐 《吉林大学学报(理学版)》 CAS CSCD 北大核心 2011年第6期1073-1078,共6页
基于Spread具有的高度灵活性和自动发现功能,构造一个基于Spread的业务支撑系统,并研究了该系统的拓扑构造,给出了系统拓扑常见的4种情况:服务节点加入、服务节点离开、动态拓扑增加和动态拓扑减少的算法.仿真实验表明,该系统具有良好... 基于Spread具有的高度灵活性和自动发现功能,构造一个基于Spread的业务支撑系统,并研究了该系统的拓扑构造,给出了系统拓扑常见的4种情况:服务节点加入、服务节点离开、动态拓扑增加和动态拓扑减少的算法.仿真实验表明,该系统具有良好的稳定性、扩展性和容灾抗毁能力. 展开更多
关键词 拓扑构造 spread中间件 算法 业务支撑系统
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一种类Spreadsheet结构的信息汇聚方法
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作者 魏永山 韩燕波 +2 位作者 孙忠林 张峰 陈欣 《计算机科学》 CSCD 北大核心 2010年第5期134-138,共5页
SpreadSheet样式的数据操作具有很好的可用性,但在SpreadSheet结构中如何表示并操纵XML数据以及如何使用复制、粘贴、移动等简单操作表示复杂的XQuery查询是两个难点问题。提出一种基于XML模式的操作表示方法,将复杂的XQuery查询语句分... SpreadSheet样式的数据操作具有很好的可用性,但在SpreadSheet结构中如何表示并操纵XML数据以及如何使用复制、粘贴、移动等简单操作表示复杂的XQuery查询是两个难点问题。提出一种基于XML模式的操作表示方法,将复杂的XQuery查询语句分解为XML模式上的粘贴节点、移动节点等操作,从而可以表示XQuery语言的核心语句FLOWR。在Spreadsheet结构中将XML模式显示为嵌套表格,用户在嵌套表格上的操作转换为XML模式上的操作。使用该方法可以构造多数据源的XQuery查询,并实现了概念验证的原型系统。与当前流行的XQuery查询构造工具相比较,原型系统更适合于无编程经验的最终用户构造XQuery查询。 展开更多
关键词 spread SHEET XQUERY 信息集成 信息资源汇聚
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THE SEEPAGE CHARACTERISTICS OF HETEROGENEOUS BODY WITH DIFFERENT SPREADING SOLUTION MODES AND ITS APPLICATIONS 被引量:1
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作者 H.J. Wang A.X. Wu +1 位作者 X.S. Chen J. Zhang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2007年第5期363-372,共10页
As the dump was a typically heterogeneous body, the seepage was different with varied spreading solution modes. The phenomenon of lamination that occured in the site was simulated using three layers in an indoor exper... As the dump was a typically heterogeneous body, the seepage was different with varied spreading solution modes. The phenomenon of lamination that occured in the site was simulated using three layers in an indoor experiment, and the seepage effect comparison experiment of the inside spreading solution model and the top spreading solution model have been carried out. In the inside spreading solution mode, the phreatic planar flew without infiltration and the parallel layer motion model was used to calculate the seepage coefficient and equivalent seepage coefficient of each state respectively. In the top spreading solution model, the phreatic planar flew with an even infiltration on the surface, and the vertical layer motion model was adopted to calculate the above coefficient. The results showed that the seepage coefficient of the inside model was larger than the top model in the heterogeneous body, The ratio of them was between 1.42 and 3.07. On the basis of these results, the following new technologies were discussed: installing a few small diameter mechanical pore sand piles with every lamination in the using dump; drilling some holes one-off in the unused dump. These two methods could changed the top spreading solution into the inside model, thus the seepage in the dump was improved. 展开更多
关键词 heterogeneous body top spreading solution inside spreading solution sand pile drawing-injection drill
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确定美式Spread期权自由边界的一种算法
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作者 吴雄华 余屹 《同济大学学报(自然科学版)》 EI CAS CSCD 北大核心 2002年第6期749-754,共6页
Spread期权是一种新型两维美式差价期权 ,即客户有权以价格E ,一份标的资产s2 交换一份标的资产s1.这种期权涉及到两标的资产且可提前执行 ,其数学模型是抛物型方程的自由边界问题 .确定期权价格的关键在于自由边界位置的确定 .通过坐... Spread期权是一种新型两维美式差价期权 ,即客户有权以价格E ,一份标的资产s2 交换一份标的资产s1.这种期权涉及到两标的资产且可提前执行 ,其数学模型是抛物型方程的自由边界问题 .确定期权价格的关键在于自由边界位置的确定 .通过坐标变换、高精度分裂算法及奇性消除方法等手段 ,计算出可靠的数值结果 . 展开更多
关键词 美式spread期权 最优执行价格 自由边界 消除奇性
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