期刊文献+
共找到5,915篇文章
< 1 2 250 >
每页显示 20 50 100
Seedling potential of trees species along the elevational gradient in temperate hill forest of central Nepal
1
作者 DANI Ram Sharan BANIYA Chitra Bahadur 《Journal of Mountain Science》 SCIE CSCD 2024年第4期1329-1344,共16页
Regeneration status of tree species along elevation gradient in temperate hill forest was not understood greatly.Present research examined the tree diversity and its regeneration patterns along an elevation gradient i... Regeneration status of tree species along elevation gradient in temperate hill forest was not understood greatly.Present research examined the tree diversity and its regeneration patterns along an elevation gradient in temperate hill forest,central Nepal.Data were collected from 300 sample plots within vertical elevation bands of 10,ranging from 1365 to 2450 m asl.A random sampling method was used for data collection in three seasons,winter,pre-monsoon and post monsoon seasons.Diameter at breast height(DBH)was used to broadly categorize the plant individual into trees,saplings and seedlings.The tree species richness ranged from 12 to 25 with density of 350 to 1200 individuals per hectare.Species richness of tree and sapling showed statistically significant unimodal pattern,which peaked at mid-elevation.Elevation showed a strong and positive linear correlation with the seedling density(Deviance=0.99,p<0.001)and a significant hump-shaped relationship with sapling density(Deviance=0.95,p<0.001).Similarly,elevations showed a statistically significant negative hump-shaped relationship with all trees,saplings and seedling stages(Deviances=0.89,0.87 and 0.57).The highest values of the Shannon-Wiener index and the lowest value of the Simpson index were found at mid-elevation for all growth forms.Nearly 92%of tree species were found at regenerating stage;49%in a good renewal regeneration status,32%in fair renewal regeneration,and 11%at a poor regenerating condition.Nevertheless,4%of tree species were reported as non-regenerating stages and 4%were newly introduced species.Hence,the regeneration status of the study area was considered fairly well since sapling(78.5%)>seedling(10.6%)≤mature(10.9%).Among tested environmental variables,elevation and annual mean rainfall were the most influential factors in the regeneration of tree species. 展开更多
关键词 Regeneration potential Chandragiri hill Altitudinal gradient Species diversity Tree species richness
下载PDF
Evaluating the Association between Human Papillomavirus and Vulvar Cancer:A Comprehensive Analysis Using Bradford Hill Criteria
2
作者 Hamid Yaz 《Journal of Clinical and Nursing Research》 2024年第7期208-218,共11页
Background:The role of human papillomavirus(HPV)in the development of vulvar cancer(VC)has been widely studied,but findings have been inconsistent.Despite numerous meta-analyses exploring the potential link between HP... Background:The role of human papillomavirus(HPV)in the development of vulvar cancer(VC)has been widely studied,but findings have been inconsistent.Despite numerous meta-analyses exploring the potential link between HPV and VC,the association remains controversial due to inherent limitations in meta-analytic methods.Objectives:To address this controversy,the study aims to investigate the potential link between HPV and VC using the Bradford Hill criteria,which offer a more comprehensive framework for establishing causation.Methodology:The study began by extracting all relevant studies on the association between HPV and VC from the PubMed database.The potential links were then assessed by examining the data using the major postulates of the Bradford Hill criteria.To ensure the reliability of the findings,the methodologies of the identified studies were critically evaluated to account for possible false-negative and false-positive results.Results:The assessment of previous studies against the Bradford Hill criteria revealed that the major postulates were not fulfilled.Conclusion:Based on the findings,it can concluded that there is no causal association between HPV and VC. 展开更多
关键词 Vulvar cancer(VC) Bradford hill criteria Human papillomavirus(HPV)
下载PDF
基于Hill肌肉模型的仿袋鼠腿悬架控制特性研究
3
作者 宋勇 刘世静 +2 位作者 李占龙 孟杰 张喜清 《太原科技大学学报》 2023年第5期403-409,共7页
为进一步改善车辆悬架的控制性能,采用仿生设计思想,提出一种基于Hill肌肉模型的仿袋鼠腿悬架(下称仿生悬架)。设计了该悬架的Fuzzy、Fuzzy-PID控制器,并采用ADAMS和Simulink联合仿真对其控制特性开展研究。研究发现:①冲击路面下,相对... 为进一步改善车辆悬架的控制性能,采用仿生设计思想,提出一种基于Hill肌肉模型的仿袋鼠腿悬架(下称仿生悬架)。设计了该悬架的Fuzzy、Fuzzy-PID控制器,并采用ADAMS和Simulink联合仿真对其控制特性开展研究。研究发现:①冲击路面下,相对于被动悬架,Fuzzy控制和Fuzzy-PID控制下的车身位移和车身加速度分别下降了54%、58%和92%、93%,悬架抗冲击性能明显改善。②随机路面下,随着路面等级和车速的增加,Fuzzy控制和Fuzzy-PID控制均可有效改善悬架的控制性能;相对于被动悬架,主动控制下的悬架表现出更加优异的缓冲隔振性能、路面适应性及稳定性;主动控制下的车身加速度传递率(8.8%~1%)呈下降趋势且数值较小,轮胎动位移(0.19~3.92)mm及其传递率(8.1%~10.5%)呈上升趋势,但数值及变化较小。③冲击路面和随机路面下,相较于Fuzzy控制,Fuzzy-PID控制下的悬架特性更优。上述结果表明,基于Hill肌肉模型的仿生悬架具有良好的控制特性,验证了该仿生思路和控制方法的正确性和有效性。 展开更多
关键词 悬架 hill肌肉模型 FUZZY控制 FUZZY-PID控制 仿袋鼠腿
下载PDF
基于肌球蛋白粗丝力学感知效应的Hill特性式理论研究
4
作者 赵晓阳 孙伟 +1 位作者 张俊萍 塔拉 《内蒙古大学学报(自然科学版)》 CAS 北大核心 2023年第6期621-628,共8页
粗丝的机械力学感知效应对于理解肌肉收缩的内在机制具有非常重要的作用。Hill特性式是描述肌肉收缩中负荷与速度关系的经验表达式,对其理论机制的研究中缺乏对粗丝力学感知效应的考虑。本文以肌肉收缩的滑行理论为依据,考虑粗丝的力学... 粗丝的机械力学感知效应对于理解肌肉收缩的内在机制具有非常重要的作用。Hill特性式是描述肌肉收缩中负荷与速度关系的经验表达式,对其理论机制的研究中缺乏对粗丝力学感知效应的考虑。本文以肌肉收缩的滑行理论为依据,考虑粗丝的力学感知效应,建立肌球蛋白与肌动蛋白丝结合的数量与粗丝承受外力的关系模型,从肌肉收缩过程中肌肉内部力的平衡角度出发,推导出肌肉收缩过程中负荷与收缩速度之间的关系即Hill特性式。结果显示理论关系式与Hill特性式完全一致,说明了肌球蛋白的力学感知效应模型的合理性,为揭示肌肉收缩的力与速度关系的潜在机制提供新的视角。 展开更多
关键词 肌肉收缩 力学感知效应 hill特性式
下载PDF
Decipher hydrocarbon generation and accumulation based on fluid inclusion and chronology:A case study from the Upper Paleozoic buried-hills in Huanghua Depression,Bohai Bay Basin 被引量:1
5
作者 Li-Hong Zhou Yong Li +5 位作者 Feng-Ming Jin Jin-Feng Xie Xiu-Gang Pu Li-Xin Fu Da Lou Yang Tian 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期1998-2008,共11页
Deciphering hydrocarbon generation and accumulation stage is of significance to understand oil and gas evolution and seek exploration targets.Taking the Upper Paleozoic buried-hills in the Huanghua Depression,Bohai Ba... Deciphering hydrocarbon generation and accumulation stage is of significance to understand oil and gas evolution and seek exploration targets.Taking the Upper Paleozoic buried-hills in the Huanghua Depression,Bohai Bay Basin,as a case study,hydrocarbon generation environment and detailed accumulation process are revealed by fluid inclusions observations,Laser Raman spectroscopy,Fourier Infrared spectroscopy,and K-Ar isotope measurements.The results show that both oil and gas inclusion were captured in the quartz overgrowth,dissolved feldspar and calcite microfractures,showing blue to dark brown fluoresce.The grains containing oil inclusions index(GOI)of oil,oil&gas and gas being 25%,65%,and 10%and the inclusions with abundant methyl groups and short chains,both indicate high thermal maturity.One series of fluids inclusion is generally observed,evidenced by the concentrated homogenization temperature of 135-145℃ and salinity of 3%-15 w.t.%NaCl equiv,indicating one primary charging stage.The gas and gas&liquid inclusions mainly contain CH_(4),with also peaks indicating CO_(2) and N_(2.)The Carboniferous and Permian biomarkers show reducing environment with brackish water,with organic matter sources both from marine and continental.The relative content ofααα20RC_(27),ααα20RC_(28),andααα20RC_(29) exhibit source contributions both from algae and higher plants,and mainly of II2 to III kerogen.Both coal derived gas and oil associated hydrocarbons are identified from most of the buried-hills.Combining the fluid homogenization temperature and salinity,as well as the thermal evolution history,the hydrocarbon generated from the Upper Paleozoic was concentrated at the end of the Eocene(40 Ma±),while the beginning of charging is 60 Ma±.The Wumaying Buried-hill is of only coal derived gas and has potential for inner coal measure natural gas exploration.The results provide a detailed understanding of hydrocarbon accumulations in the study area,which can also be reference for improving petroleum exploration efficiency in similar basins. 展开更多
关键词 Petroleum accumulation Buried hills K–Ar isotope Fluid inclusions Huanghua depression Bohai Bay Basin
下载PDF
A Darcy-Law Based Model for Heat and Moisture Transfer in a Hill Cave 被引量:1
6
作者 Fei Liu Dongliang Zhang +1 位作者 Qifu Zhu Qingyong Su 《Fluid Dynamics & Materials Processing》 EI 2023年第9期2345-2359,共15页
A hill can be regarded as an environmental carrier of heat.Water,rocks and the internal moisture naturally pre-sent in such environment constitute a natural heat accumulator.In the present study,the heat and moisture ... A hill can be regarded as an environmental carrier of heat.Water,rocks and the internal moisture naturally pre-sent in such environment constitute a natural heat accumulator.In the present study,the heat and moisture trans-fer characteristics in a representative hill cave have been simulated via a method relying on the Darcy’s law.The simulations have been conducted for both steady and unsteady conditions to discern the influence of permeability and geometric parameters on the thermal and moisture transfer processes.The reliability of the simulation has been verified through comparison of the numerical results with the annual observation data.As revealed by the numericalfindings,the internal temperature of the hill accumulator is proportional to the permeability,outside surface temperature,overground height,underground constant temperature layer depth,and underground tem-perature of the hill,and it is inversely proportional to the horizontal size of the hill.Moreover,in the considered case,the order of magnitude of the permeability of the hill is contained in the range 10-15–10-13,and displays a certain sensitivity to the rainwater seepage. 展开更多
关键词 Cave hill thermal and moisture transfer Darcy’s law temperaturefield PERMEABILITY
下载PDF
Petrographic Characteristics and Metalogeny of Zatua Hills BIFs, Haut-Uele Province (DR Congo)
7
作者 Levesque Makuku Mbo Papy-Fidèle Kombie Andeibal +3 位作者 François Tshiabo Luwanda Dominique Wetshondo Osomba Valentin Kanda Nkula Albert Ongendangenda Tienge 《Journal of Geoscience and Environment Protection》 2023年第12期163-181,共19页
Zatua Hills are located at Haut Uélé Province of Democratic Republic of Congo (DRC), between northern Bafwasende and southern Paulis (Isiro) Squarred Degrees. Belonging to greenstone belt of Ngayu, that area... Zatua Hills are located at Haut Uélé Province of Democratic Republic of Congo (DRC), between northern Bafwasende and southern Paulis (Isiro) Squarred Degrees. Belonging to greenstone belt of Ngayu, that area is identified by the high elevated zone which is remained the witness of stable zone, not affected by the ancienst erosion process. Zatua Hills are in the superior Kibalian formation dated to Neoarchaen, hosted in Upper Congo Granites Massifs of DRC covering a large central zone of NE of DRC, and consisting to dolerite, phyllade, clay rich sediment, poor Banded Iron Formations (BIFs), enriched BIFs, friable hematite, hard hematite, mineralized and unmineralized brechias. Magnetite, martite and hematite are associated to some secondary minerals such as goethite, gibbsite, kaolinite, strengite, variscite and others clay minerals present in BIFs. Petrographic analysis made from the samples collected in situ showed, as well as BIFs and iron ore associated, that magnetite was much abundant oxide mineral which is oxided to martite before to stabilize to hematite during the deposition time. Having about hundred meters of thickness, the rich iron ore of this area content, in the majority less deleterious elements which, are harmful in metallurgic process of iron. These secondary minerals were precipitated at various degrees in the leached cavities of rocks between martite and hematite aggregates to botryoidal texture and, are rich to Al, and are mainly consisting to gibbsite and solid solution series of variscite-strengite (AlPO<sub>4</sub>·2H<sub>2</sub>O and FePO<sub>4</sub>·2H<sub>2</sub>O). Low degree of metamorphism played when magnetite was converted to martite, with the presence of variscite and anatase like witnesses of this event in which, martite was crystalized to hematite. 展开更多
关键词 BIFs Zatua hills Petrographic DRC Iron Ore
下载PDF
Geochemical Signature and Metalogeny of BIFs and Associated Iron Ore of Zatua Hills, Haut-Uele Province (DR Congo)
8
作者 Levesque Makuku Mbo Dominique Wetshondo Osomba +2 位作者 Valentin Kanda Nkula Kelly Nzambe Keyila Albert Ongendangenda Tshiende 《Journal of Geoscience and Environment Protection》 2023年第10期201-217,共17页
Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has rem... Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has remained a witness to a stable zone not affected by the ancient erosion process. BIFs are most abundant and are dated to the Neoarchaean and Late Kibalian, hosted in the Upper Congo Granites Massifs of the DR. Congo. Zatua Hills consist of dolerite, phyllade, clay-rich sediment, poor itabirite, enriched BIFs, friable hematite, hard hematite, and mineralized and unmineralized breccias. Field study and geochemistry analysis by XRF, XRD, and ICP-MS are executed in order to know the geochemistry signature and paragenesis of Zatua Hills and the probably process could lead the BIFs to iron ore. The geochemistry analysis by XRF, XRD, and ICP-MS shows that Iron ore content has an iron rate between 57% and 69% with less deleterious elements such as Si, P, and Al. These deleterious elements are secondary and have silicium composition (probably quartz or chert, goethite, and Kaolinite), aluminum (probably gibbsite, variscite, cadwaladérite, goethite, and Kaolinite), phosphorous (probably variscite), and hydrated minerals, which are grown LOI in the samples. Hypogen and supergen processes are played in BIFs for iron ore conversion and, respectively, silica dissolution and leaching. Metamorphism was also impacted and marked by the Ti element (anatase) in samples, contributing to the crystallization of martite to hematite after magnetite oxidation. 展开更多
关键词 BIFs Zatua hills Geochemestry DRC Iron Ore
下载PDF
Experimental Study on Phase Characteristics of CO2 Injection in BZ13-2 Strong Volatile Oil Reservoir in Bohai Sea Buried Hills
9
作者 Zhennan Gao Lei Zhang +2 位作者 Yong Jiang Jingtao Wu Chenxu Yang 《Open Journal of Geology》 2023年第7期763-772,共10页
BZ13-2 oil field is a deep submerged strongly volatile reservoir in Bohai Sea. This oil reservoir has the characteristics of high gas oil ratio and small difference in formation pressure and saturation point pressure.... BZ13-2 oil field is a deep submerged strongly volatile reservoir in Bohai Sea. This oil reservoir has the characteristics of high gas oil ratio and small difference in formation pressure and saturation point pressure. It usually adopts gas injection development to avoid crude oil degassing and fast decreasing production capacity. However, the phase characteristics and miscibility mechanism of this high-temperature and high-pressure fluid after gas injection are not clear. Therefore, it is necessary to study the feasibility of CO<sub>2</sub> injection to improve oil recovery in near critical volatile oil reservoirs through CO<sub>2</sub> injection experiments. In the early stage of the depletion experiment, the content of heavy components in the remaining oil increased significantly, so the depletion method is not conducive to the development of such reservoirs. With the increase of CO<sub>2</sub> injection, the volumetric expansion coefficient of formation crude oil increases significantly, while the saturation pressure and formation crude oil viscosity remain basically unchanged. The minimum miscible pressure experiment shows that CO<sub>2</sub> injection under formation pressure conditions can achieve multiphase miscibility. Based on experimental research results, the BZ13-2 oilfield is suitable for early gas injection development and can significantly improve recovery. 展开更多
关键词 Bohai Buried hills Strongly Volatile Reservoir Gas Injection and Development Phase Characteristics Fine Tube Experiment
下载PDF
Hill Matrix and Radix-64 Bit Algorithm to Preserve Data Confidentiality
10
作者 Ali Arshad Muhammad Nadeem +6 位作者 Saman Riaz Syeda Wajiha Zahra Ashit Kumar Dutta Zaid Alzaid Rana Alabdan Badr Almutairi Sultan Almotairi 《Computers, Materials & Continua》 SCIE EI 2023年第5期3065-3089,共25页
There are many cloud data security techniques and algorithms available that can be used to detect attacks on cloud data,but these techniques and algorithms cannot be used to protect data from an attacker.Cloud cryptog... There are many cloud data security techniques and algorithms available that can be used to detect attacks on cloud data,but these techniques and algorithms cannot be used to protect data from an attacker.Cloud cryptography is the best way to transmit data in a secure and reliable format.Various researchers have developed various mechanisms to transfer data securely,which can convert data from readable to unreadable,but these algorithms are not sufficient to provide complete data security.Each algorithm has some data security issues.If some effective data protection techniques are used,the attacker will not be able to decipher the encrypted data,and even if the attacker tries to tamper with the data,the attacker will not have access to the original data.In this paper,various data security techniques are developed,which can be used to protect the data from attackers completely.First,a customized American Standard Code for Information Interchange(ASCII)table is developed.The value of each Index is defined in a customized ASCII table.When an attacker tries to decrypt the data,the attacker always tries to apply the predefined ASCII table on the Ciphertext,which in a way,can be helpful for the attacker to decrypt the data.After that,a radix 64-bit encryption mechanism is used,with the help of which the number of cipher data is doubled from the original data.When the number of cipher values is double the original data,the attacker tries to decrypt each value.Instead of getting the original data,the attacker gets such data that has no relation to the original data.After that,a Hill Matrix algorithm is created,with the help of which a key is generated that is used in the exact plain text for which it is created,and this Key cannot be used in any other plain text.The boundaries of each Hill text work up to that text.The techniques used in this paper are compared with those used in various papers and discussed that how far the current algorithm is better than all other algorithms.Then,the Kasiski test is used to verify the validity of the proposed algorithm and found that,if the proposed algorithm is used for data encryption,so an attacker cannot break the proposed algorithm security using any technique or algorithm. 展开更多
关键词 CRYPTOGRAPHY symmetric cipher text ENCRYPTION matrix cipher encoding decoding hill matrix 64-bit encryption
下载PDF
Distributed Trimmed Hill Estimator
11
作者 Tao Guo 《Journal of Applied Mathematics and Physics》 2023年第12期4000-4015,共16页
Proceeded from trimmed Hill estimators and distributed inference, a new distributed version of trimmed Hill estimator for heavy tail index is proposed. Considering the case where the number of observations involved in... Proceeded from trimmed Hill estimators and distributed inference, a new distributed version of trimmed Hill estimator for heavy tail index is proposed. Considering the case where the number of observations involved in each machine can be either the same or different and either fixed or varying to the total sample size, its consistency and asymptotic normality are discussed. Simulation studies are particularized to show the new estimator performs almost in line with the trimmed Hill estimator. 展开更多
关键词 Extreme Value Index Distributed Trimmed hill Estimator
下载PDF
Efficient Clustering Using Memetic Adaptive Hill Climbing Algorithm in WSN
12
作者 M.Manikandan S.Sakthivel V.Vivekanandhan 《Intelligent Automation & Soft Computing》 SCIE 2023年第3期3169-3185,共17页
Wireless Sensor Networks are composed of autonomous sensing devices which are interconnected to form a closed network.This closed network is intended to share sensitive location-centric information from a source node ... Wireless Sensor Networks are composed of autonomous sensing devices which are interconnected to form a closed network.This closed network is intended to share sensitive location-centric information from a source node to the base station through efficient routing mechanisms.The efficiency of the sensor node is energy bounded,acts as a concentrated area for most researchers to offer a solution for the early draining power of sensors.Network management plays a significant role in wireless sensor networks,which was obsessed with the factors like the reliability of the network,resource management,energy-efficient routing,and scalability of services.The topology of the wireless sensor networks acts dri-ven factor for network efficiency which can be effectively maintained by perform-ing the clustering process effectively.More solutions and clustering algorithms have been offered by various researchers,but the concern of reduced efficiency in the routing process and network management still exists.This research paper offers a hybrid algorithm composed of a memetic algorithm which is an enhanced version of a genetic algorithm integrated with the adaptive hill-climbing algorithm for performing energy-efficient clustering process in the wireless sensor networks.The memetic algorithm employs a local searching methodology to mitigate the premature convergence,while the adaptive hill-climbing algorithm is a local search algorithm that persistently migrates towards the increased elevation to determine the peak of the mountain(i.e.,)best cluster head in the wireless sensor networks.The proposed hybrid algorithm is compared with the state of art clus-tering algorithm to prove that the proposed algorithm outperforms in terms of a network life-time,energy consumption,throughput,etc. 展开更多
关键词 Wireless sensor networks TOPOLOGY CLUSTERING memetic algorithm adaptive hill climbing algorithm network management energy consumption THROUGHPUT
下载PDF
The Awakening of Consciousness:Traumatic Repetition in“Funeral Music”by Geoffrey Hill
13
作者 XING Luan-ming 《Journal of Literature and Art Studies》 2023年第9期661-664,共4页
The aftermath of the war had devastating consequences on people’s lives and society as a whole.In addition to the significant impact of the Great Depression on social production and living standards,it resulted in ps... The aftermath of the war had devastating consequences on people’s lives and society as a whole.In addition to the significant impact of the Great Depression on social production and living standards,it resulted in psychological trauma,unemployment,poverty,and social conflicts.As a prominent English poet that emerged after World War II,Geoffrey Hill depicted the gruesome realities of war through his early works.This article applies Cathy Caruth’s trauma theory to analyze Hill’s poem“Funeral Music.”The fragmented images and repetitive traumatic scenes restore the harsh realities of war.Furthermore,this article explores Joshua Pederson’s critical development of Caruth’s theoretical framework,providing an alternate perspective for textual analysis. 展开更多
关键词 TRAUMA Geoffrey hill “Funeral Music” Cathy Caruth Joshua Pederson
下载PDF
Reconstruction Design of Zaozhuang Gangue Hill Based on the Interaction of“Scenery”and“View”
14
作者 CAO Ying LIANG Zhiwei ZHANG Li 《Journal of Landscape Research》 2023年第4期9-16,共8页
Gangue hill is the associated accumulation landscape of long-term coal mining.There are a large number of gangue hills left in coal mining cities,which not only causes ecological damage but also affects the urban envi... Gangue hill is the associated accumulation landscape of long-term coal mining.There are a large number of gangue hills left in coal mining cities,which not only causes ecological damage but also affects the urban environment,thus becoming the focus of urban landscape transformation of coal mining cities.With the increase of people’s demand for ecological leisure,it has become the first choice to transform gangue hill and its surrounding areas into community parks.From the perspective of urban space and landscape system,as a huge regeneration landform in the city and a unique landscape in the mining area,gangue hill not only needs to be afforested,but also needs to be connected with mining heritages and landscape nodes in the city to form the interaction between“scenery”and“view”,so as to form an integrated mining cultural landscape system at the urban level.On the basis of this concept,taking the gangue hill of Zhongxing in Zaozhuang City as an example,this paper quantitatively analyzes the best landscape construction site in the gangue hill via viewshed analysis in GIS.Through this method,the gangue hill and Zhongxing mining heritage are closely combined,so as to establish the interactive relationship between“scenery”and“view”.It can guide the planning and design of sightseeing route and footpath system,and also provide a technical support for the design of community parks transformed from gangue hills. 展开更多
关键词 Gangue hill Zhongxing mining heritage Interaction of“scenery”and“view” Viewshed analysis
下载PDF
基于混合遗传算法的多无人机巡逻路径优化 被引量:1
15
作者 李国军 郑滋椀 +2 位作者 范英盛 卢甜甜 徐志江 《浙江大学学报(理学版)》 CAS CSCD 北大核心 2024年第1期21-28,共8页
假设无人机巡逻的起、终点均为派出所,提出了一种融合传统遗传算法和爬山算法的警用无人机巡逻路径优化模型——混合遗传算法。按照轮盘赌法则,进行种群个体的选择,以增大优秀种群个体被选中的概率,达到较好的优化效果。同时定义了与路... 假设无人机巡逻的起、终点均为派出所,提出了一种融合传统遗传算法和爬山算法的警用无人机巡逻路径优化模型——混合遗传算法。按照轮盘赌法则,进行种群个体的选择,以增大优秀种群个体被选中的概率,达到较好的优化效果。同时定义了与路径优化相适应的基因交叉和变异规则。仿真结果表明,提出的混合遗传算法在寻优效果上明显优于传统遗传算法。 展开更多
关键词 遗传算法 爬山算法 巡逻 路径优化
下载PDF
Identification and evaluation of fault-fracture reservoirs in buried hills of the Lower Paleozoic, Chengdao area, China
16
作者 Zhiwei Wang Kai Zhang +1 位作者 Yuhan Cheng Qunhu Wu 《Energy Geoscience》 2023年第3期193-202,共10页
The Bohai Bay Basin is a Meso-Cenozoic rifted basin where the Paleozoic buried hills with great hydrocarbon potentials are well developed. The reservoir space types are complex and diverse due to tectonic activities, ... The Bohai Bay Basin is a Meso-Cenozoic rifted basin where the Paleozoic buried hills with great hydrocarbon potentials are well developed. The reservoir space types are complex and diverse due to tectonic activities, making fracture distribution highly heterogeneous. Reservoir identification and mapping is challenging due to their large burial depth and poor resolution of seismic data. An integration of well-logging, seismic data interpretation and core observation is applied to identify three structural unit types in the study area, that is, fault breccia zone, fault cataclastic zone, and fault massive rock zone. A comprehensive well-logging identification template and a comprehensive discriminant function M for the reservoir are established based on the well-logging response characteristics. A M value greater than 0.12 indicates a fault breccia zone, that between 0.04 and 0.12 marks a fault cataclastic zone, and that in the range from 0.02 to 0.04 represents a fault massive rock zone. A seismic prediction method with multi-parameter fusion is proposed in the study. The large-scale fractures are mapped by coherence-clutter parameters, while small fractures are predicted via waveform indication inversion. The spatial distribution of “fault-fracture reservoirs” is precisely mapped by frequency fusion technology. It is found that the fault breccia zones usually occur close to the fault planes, while the fault cataclastic zones are slightly away from the fault planes. The hydrocarbon abundance of the breccia zones is greater than that of the fault cataclastic and fault massive rock zones. 展开更多
关键词 Buried hill Fault-facture Ieservoir Reservoir logging identication Reservoir sei smnic mapping Lower paleozoic Chengdao area
下载PDF
基于井震融合的碳酸盐岩古岩溶残丘储层刻画方法 被引量:2
17
作者 夏国朝 刘凤和 +3 位作者 杨艳 周宗良 何雄涛 张凡磊 《工程地球物理学报》 2024年第1期62-71,共10页
北大港构造带千米桥奥陶系潜山顶部发育的碳酸盐岩古岩溶残丘作为一种重要的古地貌和油气储集单元,具备良好的成藏条件,有效地刻画古岩溶残丘储层对于残丘储层的油气运移聚集分析及勘探开发有着非常重要的意义。本文首先应用地震印模法... 北大港构造带千米桥奥陶系潜山顶部发育的碳酸盐岩古岩溶残丘作为一种重要的古地貌和油气储集单元,具备良好的成藏条件,有效地刻画古岩溶残丘储层对于残丘储层的油气运移聚集分析及勘探开发有着非常重要的意义。本文首先应用地震印模法对千米桥奥陶系潜山风化壳岩溶古地貌进行精细刻画,揭示该区发育5个岩溶残丘,4个岩溶沟谷,表现为山上有山的特征;同时井震融合分析认为潜山风化壳储层大多分布在风化壳面以下0~200 m范围内,主潜山各区块风化壳残余厚度差别较大,岩溶残丘之上构造高点残余厚度大。通过成像测井和常规测井曲线上异常显示识别残丘风化壳内幕发育的岩溶洞穴,主要有大溶洞和中小溶蚀孔洞两种。应用提频地震体开展正演模拟,明确优势缝洞体储层的地震反射特征,结合张量方向场裂缝定量预测技术,能精细地预测碳酸盐岩缝洞复合体储层,以指导残丘风化壳储层油气潜力目标区的评价开发。 展开更多
关键词 古岩溶残丘 井震融合 古地貌恢复 张量方向场 岩溶储层
下载PDF
应用多时序特征的哨兵系列影像对南方丘陵区树种识别 被引量:2
18
作者 王洁 李恒凯 +1 位作者 龙北平 张建莹 《东北林业大学学报》 CAS CSCD 北大核心 2024年第3期60-68,共9页
树种分类是森林资源调查和监测的重要工作,杉木和油茶作为袁州区主要经济树种,准确获取树种空间分布信息,对产量估算和资源管理具有重要意义。以江西省宜春市袁州区为研究区,试验融合时序哨兵-1(Sentinel-1)、哨兵-2(Sentinel-2)等数据... 树种分类是森林资源调查和监测的重要工作,杉木和油茶作为袁州区主要经济树种,准确获取树种空间分布信息,对产量估算和资源管理具有重要意义。以江西省宜春市袁州区为研究区,试验融合时序哨兵-1(Sentinel-1)、哨兵-2(Sentinel-2)等数据,结合中国南方丘陵区树种特点,提取植被指数、红边植被指数、地形特征和纹理特征等构建特征变量组合,分别利用分离阈值法(SEaTH)和特征权重算法(ReliefF)进行特征重要性排序和特征优选,分析各特征对树种分类的影响。结果表明:(1)在使用光谱特征和植被-水体指数的基础上加入不同特征后,树种分类精度均有提升,其中纹理特征的加入更有利于树种分类。(2)结合随机森林算法和特征权重算法(ReliefF)对树种分类的精度最高,总体精度为85.33%,Kappa系数为0.81,优于相同特征组下的支持向量机算法和分类回归树算法。 展开更多
关键词 树种分类 哨兵-1 哨兵-2 特征优选 随机森林 中国南方丘陵
下载PDF
基于过程降雨的红层丘陵低山区滑坡灾害气象预警阈值研究 被引量:1
19
作者 易靖松 程英建 +1 位作者 徐乙 尹国龙 《水土保持通报》 CSCD 北大核心 2024年第2期215-222,235,共9页
[目的]研究不同历时降雨强度与区域滑坡灾害的关系,并对滑坡灾害的气象预警阈值进行研究,为地方管理部门地质灾害预警提供科学依据。[方法]收集了2013—2021年研究区348个雨量站的逐小时降雨数据和231处近10 a已发生灾情、险情滑坡事件... [目的]研究不同历时降雨强度与区域滑坡灾害的关系,并对滑坡灾害的气象预警阈值进行研究,为地方管理部门地质灾害预警提供科学依据。[方法]收集了2013—2021年研究区348个雨量站的逐小时降雨数据和231处近10 a已发生灾情、险情滑坡事件的时间及位置,基于平均降雨强度(I)—降雨历时(D)模型,分地貌单元,提出了不同降雨历时的临界降雨预警阈值和分级预警阈值。[结果]研究区丘陵地貌区不同前期降雨条件下1,3,6,12,24和48 h平均雨强的红色预警阈值依次为29.774,18.579,14.416,11.186,8.679和6.734 mm;低山地貌区不同前期降雨条件下1,3,6,12,24和48 h平均雨强的红色预警阈值依次为28.849,15.542,10.520,7.121,4.820和3.263 mm。[结论]在24 h前期降雨条件下,低山区对降雨的敏感性明显比丘陵区高,具体表现为低山区1,3,6,12和24 h的临界预警阈值明显比丘陵区更低,但随着降雨历时进一步延长,低山区和丘陵区域临界预警阈值趋于相近。 展开更多
关键词 平均降雨强度 降雨历时 分级预警 预警阈值 红层丘陵低山区 滑坡灾害
下载PDF
“森列”与“饾饤”:南宋园林假山营造的两种类型及其结合发展 被引量:1
20
作者 顾凯 叶聪 戴文翼 《中国园林》 CSCD 北大核心 2024年第2期124-130,共7页
现有中国园林史研究已经认识到南宋是园林中石假山营造得到重要发展的时期,然而南宋园林假山营造的具体方式及其形态特点尚未得到有效探讨。在深入研读相关文献与图像的基础上,结合历史来源与后世影响,探讨南宋园林假山营造的类型及其... 现有中国园林史研究已经认识到南宋是园林中石假山营造得到重要发展的时期,然而南宋园林假山营造的具体方式及其形态特点尚未得到有效探讨。在深入研读相关文献与图像的基础上,结合历史来源与后世影响,探讨南宋园林假山营造的类型及其发展。首先从“置”与“叠”2种基本方式出发,在历史语境中探讨“森列”与“饾饤”这2类南宋常见的假山营造类型及其来源与影响;进而关注二者在仿“飞来峰”营造中的结合与发展,从而更清晰地认识南宋,乃至其后的石假山营造。这一研究将对其后中国园林假山发展的认识,乃至当代假山特点的理解提供坚实的历史理论基础。 展开更多
关键词 风景园林 中国园林史 假山营造 南宋 飞来峰
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部