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Diversity and Inclusion:How Does ISO 30415 Affect a Company’s Business Model?
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作者 Annalisa Sentuti Francesca Sgrò +1 位作者 Federica Palazzi Gail Denisse Chamochumbi Diaz 《Chinese Business Review》 2023年第1期1-14,共14页
The International Standard Organization(ISO)published the first international certification,ISO 30415,regarding Human Resource Management-Diversity and Inclusion in May 2021.The new standard identifies a series of pri... The International Standard Organization(ISO)published the first international certification,ISO 30415,regarding Human Resource Management-Diversity and Inclusion in May 2021.The new standard identifies a series of principles,roles,actions,policies,processes,and measures that support and develop diversity and inclusion in companies.The adoption of ISO 30415 influences the entire organization,triggering a rethinking of business practices and processes and the business model’s design.In this sense,the introduction of this standard creates great challenges and opportunities for organizations.The concepts of diversity and inclusion bring out a competitive advantage for organizations looking to increase innovation and enhance their resilience,sustainability,and reputation.Despite the growing interest shown by governments,private and public institutions,and companies toward diversity and inclusion issues,empirical research on the implementation of ISO 30415 in organizations is still limited.Our paper aims to narrow this research gap by answering the following question:How does the ISO 30415 certification affect a company’s business model?Empirical research based on the qualitative analysis of a single case study was conducted to answer this question.Findings show that the main changes in the business model can be reconducted into activities devoted to creating new capabilities,establishing new partnerships,advancing technologies,and implementing new processes to promote issues of diversity and inclusion.Notably,the new capabilities,technologies,processes,and partnerships did not cause a radical business model innovation in the case analysed but rather an incremental change in the business model since the concepts of diversity and inclusion were already strongly present in the company’s culture.This study offers valuable insights into the management diversity research area.Moreover,several practical implications emerge from results that improve entrepreneurs,managers,and governments’awareness of the benefits deriving from the adoption of ISO 30415. 展开更多
关键词 diversITY INCLUSION CERTIFICATION ISO 30415 business model case study
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On models for landscape connectivity: a case study of the new-born wetland of the Yellow River Delta 被引量:4
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作者 Yue Tian-xiang Ye Qing-hua +1 位作者 Liu Qing-sheng Gong Zheng-hui 《Journal of Geographical Sciences》 SCIE CSCD 2002年第2期63-72,共10页
The models for landscape connectivity are distinguished into models for line connectivity, vertex connectivity, network connectivity and patch connectivity separately. Because the models for line connectivity, for ver... The models for landscape connectivity are distinguished into models for line connectivity, vertex connectivity, network connectivity and patch connectivity separately. Because the models for line connectivity, for vertex connectivity, and for network connectivity have long been studied and have become ripe, the model for patch connectivity is paid special attention in this paper. The patch connectivity is defined as the average movement efficiency (minimizing movement distance) of animal migrants or plant propagules in patches of a region under consideration. According to this definition, a model for landscape connectivity is mathematically deduced to apply to GIS data. The application of model for patch connectivity in the new-born wetland of the Yellow River Delta shows patch connectivity has a negative interrelation with human impact intensity and landscape diversity. 展开更多
关键词 landscape connectivity mathematical model human impact landscape diversity
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Mathematical models for foam-diverted acidizing and their applications 被引量:3
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作者 Li Songyan Li Zhaomin Lin Riyi 《Petroleum Science》 SCIE CAS CSCD 2008年第2期145-152,共8页
Foam diversion can effectively solve the problem of uneven distribution of acid in layers of different permeabilities during matrix acidizing. Based on gas trapping theory and the mass conservation equation, mathemati... Foam diversion can effectively solve the problem of uneven distribution of acid in layers of different permeabilities during matrix acidizing. Based on gas trapping theory and the mass conservation equation, mathematical models were developed for foam-diverted acidizing, which can be achieved by a foam slug followed by acid injection or by continuous injection of foamed acid. The design method for foam-diverted acidizing was also given. The mathematical models were solved by a computer program. Computed results show that the total formation skin factor, wellhead pressure and bottomhole pressure increase with foam injection, but decrease with acid injection. Volume flow rate in a highpermeability layer decreases, while that in a low-permeability layer increases, thus diverting acid to the low-permeability layer from the high-permeability layer. Under the same formation conditions, for foamed acid treatment the operation was longer, and wellhead and bottomhole pressures are higher. Field application shows that foam slug can effectively block high permeability layers, and improve intake profile noticeably. 展开更多
关键词 Foam slug foamed acid diversION ACIDIZING nonhomogenous mathematical model
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Reliability model of organization management chain of South-to-North Water Diversion Project during construction period 被引量:3
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作者 Feng Jingchun Zhou Yang +2 位作者 Hong Yuzhen Zhao Shixin Ren Xiaoqiang 《Water Science and Engineering》 EI CAS 2008年第4期107-113,共7页
In order to analyze the indispensability of the organization management chain of the South-to-North Water Diversion Project (SNWDP), two basic forms (series connection state and mixed state of both series connectio... In order to analyze the indispensability of the organization management chain of the South-to-North Water Diversion Project (SNWDP), two basic forms (series connection state and mixed state of both series connection and parallel connection) of the organization management chain can be abstracted. The indispensability of each form has been studied and is described in this paper. Through analysis of the reliability of the two basic forms, reliability models of the organization management chain in the series connection state and the mixed state of both series connection and parallel connection have been set up. 展开更多
关键词 South-to-North Water diversion Project reliability model management chain parallel connection series connection
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Penalty model for delay of bidding section construction period in South-to-North Water Diversion Eastern Route Project from perspective of programs 被引量:2
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作者 Jing-chun FENG Ya-fang REN +2 位作者 Zhong-nan DUAN Zhan-jun LIU Hai-yang LI 《Water Science and Engineering》 EI CAS 2012年第3期350-360,共11页
According to the multi-project and program management theory, this paper analyzes the program generation principle and establishes a program based on progress goals. On the basis of the present situation of calculatio... According to the multi-project and program management theory, this paper analyzes the program generation principle and establishes a program based on progress goals. On the basis of the present situation of calculation of penalty for delay of the bidding section construction period with the critical path method, we studied the effects of contractor-induced delay of the bidding section construction period in detail, including the effects on the construction period of the bidding section itself, the earliest start times of the next bidding section and other subsequent bidding sections, and the construction period of the program, and then constructed a penalty model for delay of the bidding section construction period from the perspective of programs. Using the penalty model, we conducted a practical analysis of penalty for delay of the construction period of the Baoying station program in the South-to-North Water Diversion Project. The model can help determine the amount of penalty for delay of the construction period in bidding sections scientifically and reasonably, 展开更多
关键词 program establishment program management bidding section construction period critical path method (CPM) penaly model South-to-North Water diversion Project
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Diversity Sampling Based Kernel Density Estimation for Background Modeling
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作者 毛燕芬 施鹏飞 《Journal of Shanghai University(English Edition)》 CAS 2005年第6期506-509,共4页
A novel diversity-sampling based nonparametric multi-modal background model is proposed. Using the samples having more popular and various intensity values in the training sequence, a nonparametric model is built for ... A novel diversity-sampling based nonparametric multi-modal background model is proposed. Using the samples having more popular and various intensity values in the training sequence, a nonparametric model is built for background subtraction. According to the related intensifies, different weights are given to the distinct samples in kernel density estimation. This avoids repeated computation using all samples, and makes computation more efficient in the evaluation phase. Experimental results show the validity of the diversity- sampling scheme and robustness of the proposed model in moving objects segmentation. The proposed algorithm can be used in outdoor surveillance systems. 展开更多
关键词 background subtraction diversity sampling kernel density estimation multi-modal background model
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3-D hybrid LES-RANS model for simulation of open-channel T-diversion flows 被引量:1
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作者 Jie ZHOU Cheng ZENG 《Water Science and Engineering》 EI CAS 2009年第3期13-26,共14页
The study of flow diversions in open channels plays an important practical role in the design and management of open-channel networks for irrigation or drainage. To accurately predict the mean flow and turbulence char... The study of flow diversions in open channels plays an important practical role in the design and management of open-channel networks for irrigation or drainage. To accurately predict the mean flow and turbulence characteristics of open-channel dividing flows, a hybrid LES-RANS model, which combines the large eddy simulation (LES) model with the Reynolds-averaged Navier-Stokes (RANS) model, is proposed in the present study. The unsteady RANS model was used to simulate the upstream and downstream regions of a main channel, as well as the downstream region of a branch channel. The LES model was used to simulate the channel diversion region, where turbulent flow characteristics are complicated. Isotropic velocity fluctuations were added at the inflow interface of the LES region to trigger the generation of resolved turbulence. A method based on the virtual body force is proposed to impose Reynolds-averaged velocity fields near the outlet of the LES region in order to take downstream flow effects computed by the RANS model into account and dissipate the excessive turbulent fluctuations. This hybrid approach saves computational effort and makes it easier to properly specify inlet and outlet boundary conditions. Comparison between computational results and experimental data indicates that this relatively new modeling approach can accurately predict open-channel T-diversion flows. 展开更多
关键词 hybrid LES-RANS model open-channel flow T-diversion turbulence modeling
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Modified MMS: Minimization Approach for Model Subset Selection
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作者 C.Rajathi P.Rukmani 《Computers, Materials & Continua》 SCIE EI 2023年第10期733-756,共24页
Considering the recent developments in the digital environment,ensuring a higher level of security for networking systems is imperative.Many security approaches are being constantly developed to protect against evolvi... Considering the recent developments in the digital environment,ensuring a higher level of security for networking systems is imperative.Many security approaches are being constantly developed to protect against evolving threats.An ensemble model for the intrusion classification system yielded promising results based on the knowledge of many prior studies.This research work aimed to create a more diverse and effective ensemble model.To this end,selected six classification models,Logistic Regression(LR),Naive Bayes(NB),K-Nearest Neighbor(KNN),Decision Tree(DT),Support Vector Machine(SVM),and Random Forest(RF)from existing study to run as independent models.Once the individual models were trained,a Correlation-Based Diversity Matrix(CDM)was created by determining their closeness.The models for the ensemble were chosen by the proposed Modified Minimization Approach for Model Subset Selection(Modified-MMS)from Lower triangular-CDM(L-CDM)as input.The proposed algorithm performance was assessed using the Network Security Laboratory—Knowledge Discovery in Databases(NSL-KDD)dataset,and several performance metrics,including accuracy,precision,recall,and F1-score.By selecting a diverse set of models,the proposed system enhances the performance of an ensemble by reducing overfitting and increasing prediction accuracy.The proposed work achieved an impressive accuracy of 99.26%,using only two classification models in an ensemble,which surpasses the performance of a larger ensemble that employs six classification models. 展开更多
关键词 Ensemble learning intrusion detection MINIMIZATION model diversity
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Analysis of genetic diversity and prediction of Larix species distribution in the Qinghai–Tibet Plateau,China
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作者 Qiqiang Guo Huie Li +4 位作者 Weilie Zheng Jinwen Pan Jie Lu Jiangrong Li Yu Zheng 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第3期705-715,共11页
Larix resources in the Qinghai-Tibet Plateau have important ecological and economic values.However,the lack of genetic diversity background and related research hinders the development of conservation strategies.In th... Larix resources in the Qinghai-Tibet Plateau have important ecological and economic values.However,the lack of genetic diversity background and related research hinders the development of conservation strategies.In this study,genetic diversity and distribution of fi ve Larix species were investigated.Using 19 polymorphic microsatellite markers to study 272 representative individuals from 13 populations,the results show low genetic diversity at the population level,with variation explained mainly by diff erentiation among populations.The Larix populations were classifi ed into two clades,one formed by eight populations,including three of the species in this study,L.kongboensis,L.speciosa,and L.potaninii var.australis.The other clade consists of fi ve populations,including the other two species in this study,L.griffi thii and L.himalaica.Genetic distance of the species was aff ected by geographical isolation and genetic diversity was mainly aff ected by altitude.The area suitable for Larix spp.decreased during the Last Glacial Maximum compared to the current distribution according to the niche model,but should increase in future climate scenarios(2050s),expanding westward along the Himalayas.These results provide an important scientifi c basis for the development of conservation strategies and further the sustainable utilization of Larix resources in the Qinghai-Tibet Plateau. 展开更多
关键词 Larix spp. Genetic diversity Phylogenetic relationship Genetic structure Ecological niche modeling Qinghai-Tibet Plateau
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1D-2D Hydraulic Modeling of a Diversion Channel on the Cavally River in Zouan-Hounien,Cote d’Ivoire
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作者 Kouassi Kouakou Lazare Brou Loukou Alexis +4 位作者 Yao Affoue Berthe Kouadio Zile Alex Konan Kouakou Seraphin Konan Koffi Felix Koffi Berenger 《Journal of Water Resource and Protection》 2019年第8期1036-1048,共13页
On the Cavally River, located on the border between C?te d’Ivoire and Liberia, several hydraulic structures such as bridges and diversion channels are planned to be made in recent years in the operating perimeter of ... On the Cavally River, located on the border between C?te d’Ivoire and Liberia, several hydraulic structures such as bridges and diversion channels are planned to be made in recent years in the operating perimeter of the Ity mining company. A 1D-2D hydraulic model was developed to design a diversion channel to cut a meander of the Cavally River in order to ensure hydraulic operation similar to the initial conditions of the river (water levels, flow and velocities). This model was designed with a flow rate of 240 m3/s and a Manning coefficient of 0.052 m1/3·s-1 for the minor bed and 0.06 m1/3·s-1 for the major bed. The results from the hydraulic model show that the hydraulic conditions (water levels, velocities) in the channel before and after the diversion remain almost like those of the Cavally River. 展开更多
关键词 Hydraulic modeling diversion Channel Cavally River Ity Cote d’Ivoire
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《刑事诉讼法》第四次修改与中国特色未成年人司法的发展完善 被引量:1
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作者 何挺 《南京师大学报(社会科学版)》 CSSCI 北大核心 2024年第2期124-134,共11页
《刑事诉讼法》对于我国未成年人司法的发展起到了重要的支撑与引领作用,中国特色未成年人司法具有与刑事诉讼紧密捆绑的阶段性特征。更好地调整《刑事诉讼法》与未成年人司法之间的互动关系,以推动我国未成年人司法的进一步发展完善,... 《刑事诉讼法》对于我国未成年人司法的发展起到了重要的支撑与引领作用,中国特色未成年人司法具有与刑事诉讼紧密捆绑的阶段性特征。更好地调整《刑事诉讼法》与未成年人司法之间的互动关系,以推动我国未成年人司法的进一步发展完善,应当作为《刑事诉讼法》第四次修改中涉未成年人部分修改的基本立场,并处理好两个整体性问题。一是通过吸收未成年人专门法律的普适性内容、根据其他涉未法律的新规定新增或调整专章规定、为其他法律中新增的涉未制度提供程序支撑和吸收已有司法解释或规范性文件的合理内容,来有效对接其他涉未法律规范。二是通过减少刑事诉讼整体框架和普通程序对涉未特别程序的限制,明确与成年人案件规定的梯级递进关系,来处理好与普通程序的关系。本次修改还应当整体增补与未成年被害人相关的规定,对转处制度和犯罪记录封存制度进行体系化与优化,并明确低龄严重暴力犯罪核准追诉程序的基本设置。 展开更多
关键词 《刑事诉讼法》 修改 未成年人司法 专章模式 转处
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冠状动脉CT血管造影计算FFR深度学习方法的诊断临床研究
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作者 周建昌 纪丽萍 +2 位作者 蒙志宏 张帆 曹宇佳 《中国CT和MRI杂志》 2024年第5期94-96,共3页
目的本研究旨在评估冠状动脉CT血管造影计算分流量储备(fractional flow reserve,FFR)深度学习方法的诊断准确性研究,以期为临床诊治提供参考。方法这是一项单中心的前瞻性研究,63名患者参加了深度学习FFR的诊断性能评估。为了评估冠状... 目的本研究旨在评估冠状动脉CT血管造影计算分流量储备(fractional flow reserve,FFR)深度学习方法的诊断准确性研究,以期为临床诊治提供参考。方法这是一项单中心的前瞻性研究,63名患者参加了深度学习FFR的诊断性能评估。为了评估冠状动脉狭窄的缺血风险,提出了冠状动脉三维几何形状的自动量化方法和基于深度学习的FFR预测方法。以线状FFR为参考标准,评价深度学习FFR的诊断性能。采用受试者-操作特征曲线下面积(AUC)分析确定主要评价因子。结果对于每个患者水平,以参照FFR测量的临界值≤0.8时,深度学习FFR的AUC为0.928,缺血相关病变方面比CTA狭窄严重程度0.664表现出更高的诊断性能。深度学习FFR与FFR相关(R=0.686,P<0.001),平均差值为-0.006±0.0091(P=0.619)。二次评价的准确性、敏感性、特异性分别为87.3%、97.14%、95.45%。结论深度学习FFR是一种新的方法,可以有效地评估冠状动脉狭窄的功能意义。 展开更多
关键词 冠状动脉CT血管造影 深度学习模型 分流量储备
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基于PSR优化模型的玉龙雪山生态系统多样性评价
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作者 张晓晓 赵振峰 +1 位作者 张洪 田淑静 《环境保护科学》 CAS 2024年第4期124-131,137,共9页
为对玉龙雪山自然保护区生态系统多样性保护成果做出比较科学的定量评价,以云南省丽江市玉龙纳西族自治县第三次全国土地调查、第七次全国人口普查、2020年林地一张图、2022年自然资源统一确权登记成果等为主要基础数据,在众多评价模型... 为对玉龙雪山自然保护区生态系统多样性保护成果做出比较科学的定量评价,以云南省丽江市玉龙纳西族自治县第三次全国土地调查、第七次全国人口普查、2020年林地一张图、2022年自然资源统一确权登记成果等为主要基础数据,在众多评价模型中,对保护区首次选取较为贴合、稳定的PSR模型,从压力、状态和响应等3个层次对保护区生态系统多样性进行定性和定量的评价,最终得到综合评价指标体系值7.21,表明该保护区生态系统丰富,完整性较强,受人类干扰较少,生物多样性维持功能较强。 展开更多
关键词 地理信息系统 玉龙雪山 生态系统多样性 PSR模型
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水库消落带植物多样性空间格局预测模型及环境解释--基于XGBoost-SHAP模型框架
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作者 刘瑞雪 李佳轩 李云 《生态学报》 CAS CSCD 北大核心 2024年第21期9652-9669,共18页
生物多样性的监测与预测对实现生物多样性保护及其可持续管理至关重要。传统方法通过实地调查来构建环境与生物多样性之间的多变量关系模型。空间大数据技术及机器和深度学习算法的发展为探索环境-生物多样性关系和预测生物多样性空间... 生物多样性的监测与预测对实现生物多样性保护及其可持续管理至关重要。传统方法通过实地调查来构建环境与生物多样性之间的多变量关系模型。空间大数据技术及机器和深度学习算法的发展为探索环境-生物多样性关系和预测生物多样性空间格局提供了新的视角和方法。构建了一种基于XGBoost算法的预测模型,融合实地调查的植物多样性数据和来自多源数据库的环境变量数据,分别构建了气候、地形、土壤、水文和人类活动5类共34个环境变量与植物群落物种丰富度、物种多样性和谱系多样性的关系模型,对丹江口水库消落带的植物多样性空间格局进行预测,同时结合SHAP框架确定关键环境因素;并进一步预测2050年水库消落带的植物多样性空间格局。研究表明,XGBoost算法在预测水库消落带植物多样性方面表现较好,3个多样性指标中谱系多样性的预测模型展现了最优的预测能力,而物种多样性预测模型的预测能力相对较低。结合SHAP分析发现年平均水淹时长、人类足迹与最冷季平均气温是影响消落带植物群落物种丰富度、物种多样性和谱系多样性的关键环境因素,其中年平均水淹时长的影响最为显著,随着年平均水淹时长增加,物种丰富度、物种多样性和谱系多样性降低。本研究构建的可解释预测模型可有效揭示消落带的植物多样性空间格局,为消落带生物多样性的保护和可持续管理提供科学依据,为生物多样性的监测和管理提供了新方法,对评估全球变化对生态系统的影响并促进生物多样性保护有重要意义。 展开更多
关键词 植物多样性 空间格局 预测模型 机器学习 消落带
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新型工业化与人类文明新形态 被引量:1
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作者 金碚 《China Economist》 2024年第2期31-53,共23页
人类发展和文明形态的演变和繁荣,表现为艰难地开拓畅通之途。不同文明形态间的融合畅通意味着人类文明的更大进步。人类文明进程所面临的根本问题是,多样化的文明形态如何实现相互畅通、共存共荣?工业化的基本逻辑:机器替代人力,创新... 人类发展和文明形态的演变和繁荣,表现为艰难地开拓畅通之途。不同文明形态间的融合畅通意味着人类文明的更大进步。人类文明进程所面临的根本问题是,多样化的文明形态如何实现相互畅通、共存共荣?工业化的基本逻辑:机器替代人力,创新改变世界;无论“陆权”“海权”,工业能力是实权。新型工业化的经济学叙事原则就是:脱胎于传统工业化,又升华自传统工业化;扬弃传统工业化之弊端,又发扬传统工业化之张力。经济全球化多彩新格局的形成,可以获得中国创造的人类文明新形态的建构性支撑。同时,中国的新型工业化也可以获得经济全球化新格局的更大空间和多样化体系拓展。中国新型工业化是经济全球化新格局的创造性力量,不仅创造中华文明新形态,而且促进协调解决了世界不同文明形态的共存共荣问题。经济全球化需要建立和维护的是“安全畅通、规则平等、承认差异”的世界市场经济秩序。从经济学范式的底层逻辑说,必须从工具理性的一维执念变革为理性、文化、制度三维范式承诺,以体现人类文明新形态内涵的丰富性。 展开更多
关键词 人类文明新形态 工业文明 经济增长 新型工业化 经济全球化 多样化文明形态
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引江济淮工程(河南段)水资源调配系统设计与开发 被引量:1
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作者 李赫 刘进翰 +3 位作者 左其亭 甘容 王辉 冯跃华 《南水北调与水利科技(中英文)》 CAS CSCD 北大核心 2024年第1期186-195,共10页
为强化引江济淮工程(河南段)水资源统一调配,基于Spring Boot和Vue前后端分离开发的模式,利用天地图API、WebGL、Echarts等技术设计研发引江济淮工程(河南段)水资源调配系统。从设计思路、功能界面、关键技术3个角度论述系统设计思路和... 为强化引江济淮工程(河南段)水资源统一调配,基于Spring Boot和Vue前后端分离开发的模式,利用天地图API、WebGL、Echarts等技术设计研发引江济淮工程(河南段)水资源调配系统。从设计思路、功能界面、关键技术3个角度论述系统设计思路和实现过程,从而实现地理信息服务、供需水预测、水资源优化配置、水资源优化调度等功能,实现水量分配可视化、运行调度智能化和跨流域调水管控一体化。系统测试结果表明:引江济淮工程(河南段)水资源调配系统的建立提高了受水区水资源精细化管理的水平,解决了引江济淮工程(河南段)跨流域调水的配置难题,为受水区水资源高效利用提供有效的技术支撑。 展开更多
关键词 引江济淮工程(河南段) 水资源调配系统 Spring Boot框架 Vue框架 前后端分离开发模式 水资源和谐配置
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邻近木多样性与竞争对天然云冷杉林树木生长的影响
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作者 杜宇 杨华 +2 位作者 贺丹妮 陈庆国 张晓红 《北京林业大学学报》 CAS CSCD 北大核心 2024年第8期111-121,共11页
【目的】探究天然云冷杉林邻近木多样性、竞争强度对林木生长的影响,为云冷杉林结构化经营和管理提供科学依据。【方法】选取长白山天然云冷杉林2015、2018年两期固定样地调查数据,基于结构方程模型分析邻近木多样性、竞争与树木生长的... 【目的】探究天然云冷杉林邻近木多样性、竞争强度对林木生长的影响,为云冷杉林结构化经营和管理提供科学依据。【方法】选取长白山天然云冷杉林2015、2018年两期固定样地调查数据,基于结构方程模型分析邻近木多样性、竞争与树木生长的关系。【结果】(1)研究区内天然云冷杉林的邻近木树种、径阶、树高多样性指数均集中在1.04处,3个多样性指数整体上分布均匀,树种混交度高,林分结构复杂。(2)结构方程模型中,树种、径阶、树高3个邻近木多样性指数和竞争指数对材积生长量的总影响系数分别为-0.001、0.166、0.073和-0.489,结果表明竞争是影响林木生长的关键因素。(3)径阶和树高多样性的增加对生长量均为正面影响,其中径阶多样性为直接影响,树高多样性为间接影响;树种多样性表现为直接的负面影响与间接的正面影响,总体为负面影响;此外,树种多样性的提高可以减少林木间的竞争强度,树高多样性的提高可能会导致林分结构的分化,进而促进林分中林木个体的生长。(4)研究区内林木的生长压力可能多来自于同径级林木,小径级林木生长状况较差且竞争压力较大,大中径级林木与之相反。【结论】择伐同径级或相近径级林木,同时提高林分内的径阶、树高多样性水平,可以降低林木竞争水平,促进林木个体生长,进而提高云冷杉林林分生产力。 展开更多
关键词 森林管理 采伐 结构方程模型 邻近木多样性指数 竞争 林木生长
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基于坐封受力模型的暂堵球封堵效果影响因素与参数优化
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作者 孔祥伟 时贤 +1 位作者 李赛 齐天俊 《科学技术与工程》 北大核心 2024年第13期5350-5357,共8页
暂堵球在射孔孔眼及压裂裂缝中的坐封状态影响其封堵稳定性,暂堵球封堵效果决定暂堵转向压裂技术的成败。通过建立暂堵球坐封受力计算模型,研究了压裂液排量、密度、暂堵球及孔眼参数对暂堵球坐封受力状态及其封堵效率的影响,实验模拟... 暂堵球在射孔孔眼及压裂裂缝中的坐封状态影响其封堵稳定性,暂堵球封堵效果决定暂堵转向压裂技术的成败。通过建立暂堵球坐封受力计算模型,研究了压裂液排量、密度、暂堵球及孔眼参数对暂堵球坐封受力状态及其封堵效率的影响,实验模拟了不同射孔参数、压裂排量及暂堵球/压裂液性能对封堵效果的影响。结果表明:暂堵球受拖拽力、脱离力及持球力随压裂液排量的增加而增大,暂堵球更易坐封;压裂液及暂堵球密度对暂堵球坐封封堵效率影响不大;暂堵球粒径大于孔眼直径时,暂堵球坐封封堵效率随粒径增加而增大,当暂堵球直径小于孔眼直径时,暂堵球不容易坐封;射孔孔眼数增加影响暂堵球坐封封堵效率。实验评价暂堵球最佳直径为9.0 mm,最佳泵送排量大于4.0 m^(3)/min时,有助于提高暂堵球坐封成功率,增强暂堵压裂设计的可靠性。 展开更多
关键词 水力压裂 暂堵转向 暂堵球 受力模型 坐封效率
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气候变化对南水北调西线工程的影响及建议
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作者 王国庆 虞畅 +3 位作者 金君良 宁忠瑞 王云 孙高霞 《人民黄河》 CAS 北大核心 2024年第9期60-66,共7页
南水北调工程是国家水网的重要组成部分,其西线工程建设是缓解我国西北、华北地区水资源短缺的重要举措。气候变化下西线工程引水区和受水区水资源情势直接关系到工程的规划建设与运行方式。基于历史实测资料和气候模式情景,采用数理统... 南水北调工程是国家水网的重要组成部分,其西线工程建设是缓解我国西北、华北地区水资源短缺的重要举措。气候变化下西线工程引水区和受水区水资源情势直接关系到工程的规划建设与运行方式。基于历史实测资料和气候模式情景,采用数理统计与水文模拟相结合的途径分析了气候变化对南水北调西线工程引水区和受水区水资源的影响。结果表明:1)1961—2020年西线调水区和受水区气候变化以暖湿化为主要特征,调水区年径流量整体稳定略增,受水区年径流量显著性减少。2)未来中期(2035年)和远期(2050年),调水区和受水区气温继续显著升高,降水多呈非显著增加;未来中期、远期调水区年径流量较基准期(1961—2000年)分别增加1.42%和2.08%,受水区年径流量分别减少1.02%和0.28%。3)未来气候变化下,调水区年径流量相对稳定,能够满足调水需求,受水区年径流量略减,对跨流域调水需求有所增加。为确保南水北调西线工程的长期稳定运行,建议加强气候变化及其影响的不确定性研究,制定科学合理的应对措施,以应对未来可能的水资源短缺的挑战。 展开更多
关键词 气候变化 RCCC-WBM模型 水资源 南水北调西线工程
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不同营养水平调水对贡湖湾湖区水质及浮游藻类影响的模拟研究
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作者 杨倩倩 吴时强 +3 位作者 吴修锋 戴江玉 吕学研 薛万云 《中国农村水利水电》 北大核心 2024年第8期8-17,共10页
为探究“引江济太”工程调水给受水湖区水体带来的生态效应,采用水生微宇宙模型进行为期11 d的室内模拟实验,以太湖贡湖湾湖区为受水水体,引入3组设定好的不同营养盐水平(贫营养水平O、中营养水平M、富营养水平E)的望虞河河水,研究在不... 为探究“引江济太”工程调水给受水湖区水体带来的生态效应,采用水生微宇宙模型进行为期11 d的室内模拟实验,以太湖贡湖湾湖区为受水水体,引入3组设定好的不同营养盐水平(贫营养水平O、中营养水平M、富营养水平E)的望虞河河水,研究在不同营养盐水平调水影响下,受水水体水生态环境的动态响应过程。结果表明:整个实验过程中,中营养和贫营养调水组的水体TN、NO_(3)^(-)-N、NH4_(+)-N、TP、SRP、TOC含量下降明显,富营养调水组影响效果较中营养和贫营养调水组差;调水提高了受水水体生态系统的多样性和均匀度水平,硅藻等非蓝藻细胞密度增加,蓝藻细胞生长受到竞争胁迫,中营养和贫营养调水的影响作用效果好于富营养水平。RDA分析结果表明,受水水体的pH、DO、SiO_(3)^(2-)-Si、TDS、NO_(3)^(-)-N、SRP是本实验水体影响藻类群落结构的主要环境驱动因子。 展开更多
关键词 “引江济太”工程 贡湖湾 水生微宇宙模型 浮游藻类群落 环境因子
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