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Quantitative Analysis of Seeing with Height and Time at Muztagh-Ata Site Based on ERA5 Database
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作者 Xiao-Qi Wu Cun-Ying Xiao +3 位作者 Ali Esamdin Jing Xu Ze-Wei Wang Luo Xiao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第1期87-95,共9页
Seeing is an important index to evaluate the quality of an astronomical site.To estimate seeing at the Muztagh-Ata site with height and time quantitatively,the European Centre for Medium-Range Weather Forecasts reanal... Seeing is an important index to evaluate the quality of an astronomical site.To estimate seeing at the Muztagh-Ata site with height and time quantitatively,the European Centre for Medium-Range Weather Forecasts reanalysis database(ERA5)is used.Seeing calculated from ERA5 is compared consistently with the Differential Image Motion Monitor seeing at the height of 12 m.Results show that seeing decays exponentially with height at the Muztagh-Ata site.Seeing decays the fastest in fall in 2021 and most slowly with height in summer.The seeing condition is better in fall than in summer.The median value of seeing at 12 m is 0.89 arcsec,the maximum value is1.21 arcsec in August and the minimum is 0.66 arcsec in October.The median value of seeing at 12 m is 0.72arcsec in the nighttime and 1.08 arcsec in the daytime.Seeing is a combination of annual and about biannual variations with the same phase as temperature and wind speed indicating that seeing variation with time is influenced by temperature and wind speed.The Richardson number Ri is used to analyze the atmospheric stability and the variations of seeing are consistent with Ri between layers.These quantitative results can provide an important reference for a telescopic observation strategy. 展开更多
关键词 site testing atmospheric effects methods:data analysis telescopes EARTH
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The environmental analysis and site selection of mussel and large yellow croaker aquaculture areas based on high resolution remote sensing
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作者 Lina Cai Jie Yin +3 位作者 Xiaojun Yan Yongdong Zhou Rong Tang Menghan Yu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第3期66-86,共21页
Mussel aquaculture and large yellow croaker aquaculture areas and their environmental characteristics in Zhoushan were analyzed using satellite data and in-situ surveys.A new two-step remote sensing method was propose... Mussel aquaculture and large yellow croaker aquaculture areas and their environmental characteristics in Zhoushan were analyzed using satellite data and in-situ surveys.A new two-step remote sensing method was proposed and applied to determine the basic environmental characteristics of the best mussel and large yellow croaker aquaculture areas.This methodology includes the first step of extraction of the location distribution and the second step of the extraction of internal environmental factors.The fishery ranching index(FRI1,FRI2)was established to extract the mussel and the large yellow croaker aquaculture area in Zhoushan,using Gaofen-1(GF-1)and Gaofen-6(GF-6)satellite data with a special resolution of 2 m.In the second step,the environmental factors such as sea surface temperature(SST),chlorophyll a(Chl-a)concentration,current and tide,suspended sediment concentration(SSC)in mussel aquaculture area and large yellow croaker aquaculture area were extracted and analyzed in detail.The results show the following three points.(1)For the extraction of the mussel aquaculture area,FRI1 and FRI2 are complementary,and the combination of FRI1 and FRI2 is suitable to extract the mussel aquaculture area.As for the large yellow croaker aquaculture area extraction,FRI2 is suitable.(2)Mussel aquaculture and the large yellow croaker aquaculture area in Zhoushan are mainly located on the side near the islands that are away from the eastern open waters.The water environment factor template suitable for mussel and large yellow croaker aquaculture was determined.(3)This two-step remote sensing method can be used for the preliminary screening of potential site selection for the mussels and large yellow croaker aquaculture area in the future.the fishery ranching index(FRI1,FRI2)in this paper can be applied to extract the mussel and large yellow croaker aquaculture areas in coastal waters around the world. 展开更多
关键词 mussel aquaculture area large yellow croaker aquaculture area high resolution satellite site selection environmental analysis
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Design & Test of an Advanced Web Security Analysis Tool (AWSAT)
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作者 Meenakshi S. P. Manikandaswamy Vijay Madisetti 《Journal of Software Engineering and Applications》 2024年第5期448-461,共14页
Considering the escalating frequency and sophistication of cyber threats targeting web applications, this paper proposes the development of an automated web security analysis tool to address the accessibility gap for ... Considering the escalating frequency and sophistication of cyber threats targeting web applications, this paper proposes the development of an automated web security analysis tool to address the accessibility gap for non-security professionals. This paper presents the design and implementation of an automated web security analysis tool, AWSAT, aimed at enabling individuals with limited security expertise to effectively assess and mitigate vulnerabilities in web applications. Leveraging advanced scanning techniques, the tool identifies common threats such as Cross-Site Scripting (XSS), SQL Injection, and Cross-Site Request Forgery (CSRF), providing detailed reports with actionable insights. By integrating sample payloads and reference study links, the tool facilitates informed decision-making in enhancing the security posture of web applications. Through its user-friendly interface and robust functionality, the tool aims to democratize web security practices, empowering a wider audience to proactively safeguard against cyber threats. 展开更多
关键词 Web Security Automated analysis Vulnerability Assessment Web Scanning Cross-site Scripting SQL Injection Cross-site Request Forgery
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Temperature-Triggered Hardware Trojan Based Algebraic Fault Analysis of SKINNY-64-64 Lightweight Block Cipher
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作者 Lei Zhu Jinyue Gong +1 位作者 Liang Dong Cong Zhang 《Computers, Materials & Continua》 SCIE EI 2023年第6期5521-5537,共17页
SKINNY-64-64 is a lightweight block cipher with a 64-bit block length and key length,and it is mainly used on the Internet of Things(IoT).Currently,faults can be injected into cryptographic devices by attackers in a v... SKINNY-64-64 is a lightweight block cipher with a 64-bit block length and key length,and it is mainly used on the Internet of Things(IoT).Currently,faults can be injected into cryptographic devices by attackers in a variety of ways,but it is still difficult to achieve a precisely located fault attacks at a low cost,whereas a Hardware Trojan(HT)can realize this.Temperature,as a physical quantity incidental to the operation of a cryptographic device,is easily overlooked.In this paper,a temperature-triggered HT(THT)is designed,which,when activated,causes a specific bit of the intermediate state of the SKINNY-64-64 to be flipped.Further,in this paper,a THT-based algebraic fault analysis(THT-AFA)method is proposed.To demonstrate the effectiveness of the method,experiments on algebraic fault analysis(AFA)and THT-AFA have been carried out on SKINNY-64-64.In the THT-AFA for SKINNY-64-64,it is only required to activate the THT 3 times to obtain the master key with a 100%success rate,and the average time for the attack is 64.57 s.However,when performing AFA on this cipher,we provide a relation-ship between the number of different faults and the residual entropy of the key.In comparison,our proposed THT-AFA method has better performance in terms of attack efficiency.To the best of our knowledge,this is the first HT attack on SKINNY-64-64. 展开更多
关键词 SKINNY-64-64 lightweight block cipher algebraic fault analysis Hardware Trojan residual entropy
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Comparative Genomic Analysis of Enterovirus 71 Revealed Six New Potential Neurovirulence-associated Sites 被引量:5
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作者 JIA Qing Jun CHEN Xin Yu +4 位作者 LI De Zhou XU Juan Juan XU Zhi Gang DUAN Zhi Liang WEN Jin Sheng 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2016年第10期767-772,共6页
In the present study,the complete genomes of four common(4/EV71/Wenzhou/CHN/2014,15/EV71/Wenzhou/CHN/2014,116/EV71/Wenzhou/CHN/2014,and 120/EV71/Wenzhou/CHN/2014)and two virulent(11/EV71/Wenzhou/CHN/2014and 109/EV7... In the present study,the complete genomes of four common(4/EV71/Wenzhou/CHN/2014,15/EV71/Wenzhou/CHN/2014,116/EV71/Wenzhou/CHN/2014,and 120/EV71/Wenzhou/CHN/2014)and two virulent(11/EV71/Wenzhou/CHN/2014and 109/EV71/Wenzhou/CHN/2014)enterovirus 71(EV71)isolates were sequenced and described.They are 7405 bp in length and belong to EV71 sub-genotype C4 (C4a cluster). 展开更多
关键词 CHN UTR EV Comparative Genomic analysis of Enterovirus 71 Revealed Six New Potential Neurovirulence-associated sites
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A Comparative Analysis of the New -3(-n) - 1 Remer Conjecture and a Proof of the 3n + 1 Collatz Conjecture
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作者 Mike Remer 《Journal of Applied Mathematics and Physics》 2023年第8期2216-2220,共5页
This scientific paper is a comparative analysis of two mathematical conjectures. The newly proposed -3(-n) - 1 Remer conjecture and how it is related to and a proof of the more well known 3n + 1 Collatz conjecture. An... This scientific paper is a comparative analysis of two mathematical conjectures. The newly proposed -3(-n) - 1 Remer conjecture and how it is related to and a proof of the more well known 3n + 1 Collatz conjecture. An overview of both conjectures and their respective iterative processes will be presented. Showcasing their unique properties and behavior to each other. Through a detailed comparison, we highlight the similarities and differences between these two conjectures and discuss their significance in the field of mathematics. And how they prove each other to be true. 展开更多
关键词 -3(-n) - 1 Remer Conjecture 3n + 1 Collatz Conjecture Comparative analysis PROOF Natural Numbers Integer Sequences Factorial Processes Par-tial Differential Equations Bounded Values Collatz Conjecture Collatz Algo-rithm Collatz Operator Collatz Compliance And Mathematical Conjectures
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GIS and Multicriteria Decision Analysis for Landfill Site Selection in Al-Hashimyah Qadaa
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作者 Mohammad Ali Alanbari Nadhir Al-Ansari Hadeel Kareem Jasim 《Natural Science》 2014年第5期282-304,共23页
Waste management system is not well regulated in Iraq. Despite the fact that there are various techniques used for solid waste disposal, landfill is the most common mode for the disposal of solid waste in Iraq, landfi... Waste management system is not well regulated in Iraq. Despite the fact that there are various techniques used for solid waste disposal, landfill is the most common mode for the disposal of solid waste in Iraq, landfill site selection criteria is quite complex process and it depends on several regulation and factors. In this study landfill site selection is performed by using Multicriteria Decision Analysis (MCDA) and Geographic Information System (GIS) for the Al-Hashimyahqadaa. Existing landfills in qadaa are temporary and/or non-conforming to the environmental conditions. In order to determine landfill site, several criteria were examined such as urban centers, land use, airports, pipes, power lines, railways, roads, slope, streams, surface water, industrial areas, oil pipes, liquid gas pipes, soil types are prepared. MCDA was used to measure the relative importance weighting for each criterion. Each map layer was prepared using GIS and the final suitable map was created by overlay analyses of each criterion map. According to the results, high and low suitable areas were determined in the study area. Field site check was performed to determine the accuracy and suitability of the candidate sites. 展开更多
关键词 GIS MULTICRITERIA DECISION analysis LANDFILL site SELECTION CRITERIA
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Implications for Cultural Landscape in a Chinese Context: Geo-analysis of Spatial Distribution of Historic Sites 被引量:5
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作者 WANG Fang MAO Wen +1 位作者 DONG Ying ZHU Xiaohua 《Chinese Geographical Science》 SCIE CSCD 2018年第1期167-182,共16页
The protection of historic sites, especially their relationship with urban development, has become a worldwide issue, both in developed and developing countries. In the context of rapid urbanization in China, the real... The protection of historic sites, especially their relationship with urban development, has become a worldwide issue, both in developed and developing countries. In the context of rapid urbanization in China, the realistic compatibility between urban construction and the protection of historic sites is always a key research topic. In this study, first, to comprehend their spatial distribution patterns, 828 historic sites throughout the country are selected based on certain criteria. Then, we conduct quantitative research using GIS software, adopting indicators that include Nearest Neighbor Index, Gini Coefficient, and Geographic Concentration Index to analyze the spatial characteristics of historic sites on the three levels of city, province and nation. The results indicate that the spatial distribution of the different types of historic sites is an agglomeration on the nationwide scale, most of which is located in the regions of the Pearl(Zhujiang) River Delta, Yangtze(Changjiang) River Delta and Beijing-Tianjin Region. Because the majority of historic sites are located within approximately 10 km of the downtown area, a certain pattern has emerged, showing that the larger cities own more historic areas, which are in a more incomplete state of preservation, indicating the fragmentation of heritage spaces. The formation mechanism of the historic sites' distribution pattern is based on the conditions of the cities/towns as well as the bid-rent theory. 展开更多
关键词 分发模式 空间特征 上下文 历史 地点 中国 GEO 风景
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Optimal site selection for an optical-astronomical observatory in Pakistan using Multicriteria Decision Analysis
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作者 Daniyal Syed Jamil Hassan Kazmi 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第9期71-78,共8页
An astronomical observatory is the core component of any astronomical research facility that connects astronomers with their lab: the Cosmos. The research quality of an astronomical facility is rooted in the precision... An astronomical observatory is the core component of any astronomical research facility that connects astronomers with their lab: the Cosmos. The research quality of an astronomical facility is rooted in the precision of data, collected by its observatory. For optimal performance, an observatory is sited while considering certain astronomical, environmental, geological and social parameters. This study aims to identify the potential sites in Pakistan for locating an optical-astronomical observatory using the Multicriteria Decision Analysis(MCDA) technique. The study uses the Analytic Hierarchy Process(AHP) for deriving the influence weights of nine evaluation criteria: Photometric Night Fraction;Night-time Sky Brightness;Sky Transparency;Aerosol Concentration;Altitude;Terrain Slope;Accessibility;Seismic Vulnerability;and Landuse/Land Cover. On the basis of experts’ opinions and previous studies, the evaluation criteria have been ordered in two possible preference sequences for identifying their influence weights with respect to each other for taking part in MCDA. Consequently, the process of MCDA identified certain areas with respect to each preference sequence, whereas some areas were found to be suitable according to both preference sequences. The study synchronizes the required eclectic data into an evaluation matrix that augments the process of astronomical site selection. In the future, this study will be useful for astronomical societies and for furthering astronomical research in the country. 展开更多
关键词 astronomical INSTRUMENTATION METHODS and techniques:data analysis METHODS and techniques:site testing general:miscellaneous
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Spatial Analysis and Modelling of Wind Farm Site Suitability in Nasarawa State, North-Central Nigeria
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作者 Chukwunonso Emmanuel Ozim Anita Odionyenfe Nweke +3 位作者 Salamatu Abraham Ekpo Olufemi Stephen Oladeinde Haruna Kuje Ayuba Udochukwu Michael Mbanaso 《Journal of Geographic Information System》 2021年第5期603-630,共28页
There has been an increasing global and local interest in developing renewable, clean, and cheap energy towards achieving Goal number 7 of the Sustainable Development Goals (SDG). However, decisions involving suitable... There has been an increasing global and local interest in developing renewable, clean, and cheap energy towards achieving Goal number 7 of the Sustainable Development Goals (SDG). However, decisions involving suitable and sustainable locations for renewable energy projects remain an important task. This study employed Geographic Information System (GIS) and Multi-Criteria Decision Analysis (MCDA) to spatially analyze and model wind farm site suitability in Nasarawa State. The aim is to integrate the environmental, social, and economic aspects of decision-making for identifying sustainable wind farm sites. The study distinguished between two sets of decision criteria: decision constraints and decision factors. The former defined the exclusion zones while the latter were standardized based on fuzzy logic to depict varying degrees of suitability across the State. The MCDA applied the weighted linear combination method, with relative weights generated through pairwise comparisons of the analytic hierarchy process to analyze three policy scenarios: equal weights, environmental/social priority, and economic priority scenario. A combination of resulting composite maps from the constraints and the factors gave the final suitability maps. The resulting suitability index (SI) for the respective policy scenario describes the degrees of suitability: Ideal locations were denoted by one (1) and the not suitable locations by zero (0), with values in-between depicting varying degrees of wind farm site suitability. Based on the SI, priority locations indicating areas with good prospects, in addition to the most suitable parcels of land, were identified and delineated. The composite decision constraint revealed that wind farm projects would not be viable in more than half (57.58%) of the State. Wind speed was the major constraint and accounted for the exclusion of 46.25%, with a mean fuzzy membership value of 0.2008 indicating low suitability across the State. Also, the average acceptable wind farm location for the three-policy scenario was 33.33% of the entire study area. Lafia, Obi, Keana, Awe, Nasarawa-Eggon, Wamba and Kokona LGAs were the identified priority Local Government Areas (LGAs). However, only Lafia, Obi, and Nasarawa-Eggon were consistent with changes in the policy objectives. All the priority LGAs have one or more of the most suitable parcels within their administrative boundaries except for Wamba. Despite the severe limitations of wind speed, substantial parts of Nasarawa State still provide great development potentials for wind energy. The “most suitable” locations in Lafia, Nasarawa-Eggon, and Obi LGAs should have first consideration for the development of wind energy in the State. 展开更多
关键词 GIS Multi-Criteria Spatial analysis and Modelling Wind Energy Farm site Suitability Nasarawa State Nigeria
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Sanitary Landfill Site Selection Using Multi-criteria Analysis Evaluation:Case Study of Dibra Region,Albania
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作者 Neritan Shkodrani Oltion Marko +1 位作者 Konalsi Gjoka Joana Gjipalaj 《Journal of Environmental Science and Engineering(A)》 2022年第3期87-94,共8页
Landfill is a common solution for the final disposal of MSW(Municipal Solid Waste)in Albania.Landfill sitting is an extremely difficult task to accomplish because the site selection process depends on different factor... Landfill is a common solution for the final disposal of MSW(Municipal Solid Waste)in Albania.Landfill sitting is an extremely difficult task to accomplish because the site selection process depends on different factors and regulations.To ensure that an appropriate site is chosen,a systematic process should be developed and followed.In this study,10 candidate sites for an appropriate landfill area in Dibra Region are determined by using the MCE(Multi-criteria Evaluation).From the application of the exclusion criteria provided in the study methodology,it was able to find the best three alternatives.The statistical processing for the determination of the best place was accomplished through MCA(Multi-criteria Analysis)and Environmental Management,for three scenarios with different weights of criteria.The application of this method has led to the identification of the most suitable site for the construction of sanitary landfill in the Dibra Region. 展开更多
关键词 MCDA(Multi-criteria Decision analysis) LANDFILL waste management site selection Albania
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Groundwater flow analysis in the coastal multi-layer aquifer at the planned construction site of subsurface dam
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《Global Geology》 1998年第1期5-5,共1页
关键词 FLOW Groundwater flow analysis in the coastal multi-layer aquifer at the planned construction site of subsurface dam
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Analysis and research of long-term stability about the gob site in Northern Shaanxi Province
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作者 ZHANG Zhi-pei PENG Hui 《Journal of Coal Science & Engineering(China)》 2011年第1期16-21,共6页
关键词 煤矿采空区 陕西省 场地稳定性 有限元分析 长期稳定性 开采方式 开采过程 变化规律
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社区尺度斜入射波场下场地-建筑群耦合作用模拟方法
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作者 巴振宁 付继赛 +2 位作者 王方博 梁建文 牛嘉琪 《振动与冲击》 EI CSCD 北大核心 2024年第4期1-11,37,共12页
场地-城市相互作用(site-city interaction,SCI)效应会显著改变场地地震波场分布及建筑反应,基于SCI效应理论计算研究方法的发展现状,发挥谱元(spectral element,SE)法可快速高效求解三维地震波场传播和多自由度(multi-degree of freedo... 场地-城市相互作用(site-city interaction,SCI)效应会显著改变场地地震波场分布及建筑反应,基于SCI效应理论计算研究方法的发展现状,发挥谱元(spectral element,SE)法可快速高效求解三维地震波场传播和多自由度(multi-degree of freedom,MDOF)模型计算量小且可同时模拟大量建筑的优势,同时,结合频率波数域(frequency wave number analysis,FK)方法,以等效地震荷载的方式施加地震波场,建立了FK-SE-MDOF耦合方法,实现了SE-MDOF耦合模型中多种波型(P波、SV波和SH波)的斜入射输入,解决了当前三维SCI效应研究方法中未能同时考虑建筑非线性、频谱特性、地震波波型及入射角度影响的问题。首先对方法原理进行了介绍;然后,通过与振动台试验的对比,验证了方法的正确性;进而,采用该方法建立理想场地-城市建筑群相互作用耦合模型,主要探讨了入射角度和地震波波型对SCI效应的影响,得到了一些有益结论。该方法较为真实地反映SCI效应影响的同时,可反映建筑基础轮廓对地震波场的影响,适用于需考虑建筑轮廓信息的社区尺度SCI效应研究,可为城市规划、抗震设计、风险评估以及震后救援等工作提供定量指导。 展开更多
关键词 场地-城市相互作用(SCI) 频率波数域-谱元-多自由度模型(FK-SE-MDOF)方法 斜入射 建筑群 社区尺度
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Integrated use of GIS, remote sensing and multi-criteria decision analysis to assess ecological land suitability in multi-functional forestry 被引量:5
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作者 Naser Ahmadi Sani Sasan Babaie Kafaky +1 位作者 Timo Pukkala Asadollah Mataji 《Journal of Forestry Research》 SCIE CAS CSCD 2016年第5期1127-1135,共9页
The Zagros forests are a treasure of valuable oak forests, but they have been severely degraded from long-term misuse. Geographic information systems (GIS) and multi-criteria decision analysis (MCDA) have been inc... The Zagros forests are a treasure of valuable oak forests, but they have been severely degraded from long-term misuse. Geographic information systems (GIS) and multi-criteria decision analysis (MCDA) have been increasingly used to improve the management of vulnerable ecosystems to prevent further degradation and increase the sustainability of land use. This study presents a methodology to assess land suitability using remote sensing (RS) to obtain wall-to-wall data for the calculations, GIS to analyze the data, and MCDA to rank alternative land uses. The criteria and subcriteria affecting the suitability of land for different uses were identified and weighted using an analytic hierarchy process. Variables used as subcriteria were assessed using satellite data and other sources of information such as existing maps and field surveys. Numerical values for the subcriteria were classified, and each class was given a priority rating according to expert judgments. Based on the ratings and weights of the subcriteria, a priority map was created for each land use using the weighted linear combination method. The priority maps for different land uses were overlaid to obtain a preliminary land use map, which often indicated several simultaneous land uses for the same location. The preliminary map was further edited by removing unrealistic, mutually exclusive land-use combinations. The study tested and demonstrated the potential of integrating RS, G1S and MCDA techniques for solving complicated land allocation problems in forested regions using a scientifically sound and practical approach for efficient and sustainable allocation of forestland for different uses. 展开更多
关键词 Analytic hierarchy process Decisionanalysis Ecological suitability Land allocation Land-use planning - Spatial analysis - Zagros forests
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Symplectic analysis for elastic wave propagation in two-dimensional cellular structures 被引量:5
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作者 Xiu-Hui Hou Zi-Chen Deng +1 位作者 Jia-Xi Zhou Tie-Quan Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第5期711-720,共10页
On the basis of the finite element analysis, the elastic wave propagation in cellular structures is investigated using the symplectic algorithm. The variation principle is first applied to obtain the dual variables an... On the basis of the finite element analysis, the elastic wave propagation in cellular structures is investigated using the symplectic algorithm. The variation principle is first applied to obtain the dual variables and the wave propagation problem is then transformed into two-dimensional (2D) symplectic eigenvalue problems, where the extended Wittrick-Williams algorithm is used to ensure that no phase propagation eigenvalues are missed during computation. Three typical cellular structures, square, triangle and hexagon, are introduced to illustrate the unique feature of the symplectic algorithm in higher-frequency calculation, which is due to the conserved properties of the structure-preserving symplectic algorithm. On the basis of the dispersion relations and phase constant surface analysis, the band structure is shown to be insensitive to the material type at lower frequencies, however, much more related at higher frequencies. This paper also demonstrates how the boundary conditions adopted in the finite element modeling process and the structures' configurations affect the band structures. The hexagonal cells are demonstrated to be more efficient for sound insulation at higher frequencies, while the triangular cells are preferred at lower frequencies. No complete band gaps are observed for the square cells with fixed-end boundary conditions. The analysis of phase constant surfaces guides the design of 2D cellular structures where waves at certain frequencies do not propagate in specified directions. The findings from the present study will provide invaluable guidelines for the future application of cellular structures in sound insulation. 展开更多
关键词 Cellular structures Symplectic analysis Dispersion relation - Phase constant surface Sound insulation
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Algebraic Solution for the Forward Displacement Analysis of the General 6-6 Stewart Mechanism 被引量:8
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作者 WEI Feng WEI Shimin +1 位作者 ZHANG Ying LIAO Qizheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第1期56-62,共7页
The solution for the forward displacement analysis(FDA) of the general 6-6 Stewart mechanism(i.e., the connection points of the moving and fixed platforms are not restricted to lying in a plane) has been extensive... The solution for the forward displacement analysis(FDA) of the general 6-6 Stewart mechanism(i.e., the connection points of the moving and fixed platforms are not restricted to lying in a plane) has been extensively studied, but the efficiency of the solution remains to be effectively addressed. To this end, an algebraic elimination method is proposed for the FDA of the general 6-6 Stewart mechanism. The kinematic constraint equations are built using conformal geometric algebra(CGA). The kinematic constraint equations are transformed by a substitution of variables into seven equations with seven unknown variables. According to the characteristic of anti-symmetric matrices, the aforementioned seven equations can be further transformed into seven equations with four unknown variables by a substitution of variables using the Grobner basis. Its elimination weight is increased through changing the degree of one variable, and sixteen equations with four unknown variables can be obtained using the Grobner basis. A 40th-degree univariate polynomial equation is derived by constructing a relatively small-sized 9 × 9 Sylvester resultant matrix. Finally, two numerical examples are employed to verify the proposed method. The results indicate that the proposed method can effectively improve the efficiency of solution and reduce the computational burden because of the small-sized resultant matrix. 展开更多
关键词 general 6-6 Stewart mechanism forward displacement analysis (FDA) conformal geometric algebra (CGA) Gr6bner basis Sylvester resultant
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Numerical Analysis of the Adhesive Forces in Nano-Scale Structure 被引量:1
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作者 Young-Sam Cho Houkseop Han Wan-Doo Kim 《Journal of Bionic Engineering》 SCIE EI CSCD 2006年第4期209-216,共8页
Nanohairs, which can be found on the epidermis of Tokay gecko's toes, contribute to the adhesion by means of van der Waals force, capillary force, etc. This structure has inspired many researchers to fabricate the at... Nanohairs, which can be found on the epidermis of Tokay gecko's toes, contribute to the adhesion by means of van der Waals force, capillary force, etc. This structure has inspired many researchers to fabricate the attachable nano-scale structures. However, the efficiency of artificial nano-scale structures is not reliable sufficiently. Moreover, the mechanical parameters related to the nano-hair attachment are not yet revealed qualitatively. The mechanical parameters which have influence on the ability of adhesive nano-hairs were investigated through numerical simulation in which only van der Waals force was considered. For the numerical analysis, finite element method was utilized and van der Waals force, assumed as 12-6 Lennard-Jones potential, was implemented as the body force term in the finite element formulation. 展开更多
关键词 NUMERICAL analysis adhesive force nano-scale structure finite element model van der Waals force 12-6 L-J potential
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Analytical solution for vertical site response analysis and its validation
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作者 Liu Junwei Zhang Xiao +2 位作者 Cao Zewei Han Bo Yang Shizeng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第1期53-60,共8页
Existing studies for site response analysis in geotechnical earthquake engineering have widely concentrated on the horizontal component of the ground motion. However, strong vertical ground motions have been repeatedl... Existing studies for site response analysis in geotechnical earthquake engineering have widely concentrated on the horizontal component of the ground motion. However, strong vertical ground motions have been repeatedly observed, resulting in significant vertical compression damage of engineering structures. Furthermore, for the seismic design of critical structures(e.g. large-scale dams and nuclear power plants), the ground motions in all three directions should be considered. Therefore, there is a need to investigate the site response subjected to the vertical component of the ground motion, especially for the seismic design of critical structures. Consequently, in this study, a numerical program for vertical site response analysis is proposed based on the commonly used analytical transfer function method. The proposed program is then validated against well-documented case studies obtained from the Japanese KiK-net(Kiban Kyoshin network) downhole array monitoring system. Results show that the response spectra at the ground surface are well predicted in the low frequency range(<5 Hz), while discrepancies are observed in the high frequency range. However, the high frequency discrepancies do not significantly affect the overall prediction accuracy, as the overall seismic response of geotechnical structures are usually dominated by low frequency vibrations. Furthermore, the limitations in the analysis are also discussed. 展开更多
关键词 site response analysis VERTICAL ground MOTIONS TRANSFER function ANALYTICAL solution
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Properties study and phylogenetic analysis of a bacterial strain with high de-emulsification efficiency 被引量:1
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作者 侯宁 杨基先 +4 位作者 马放 李大鹏 温沁雪 徐暘 郭静波 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第3期350-354,共5页
For further practical application,the phylogenetic analysis and de-emulsification properties study of strain XH1 with high de-emulsification efficiency isolated from crude oil contaminated soil in Daqing oil field wer... For further practical application,the phylogenetic analysis and de-emulsification properties study of strain XH1 with high de-emulsification efficiency isolated from crude oil contaminated soil in Daqing oil field were conducted with a surfactant-stabilized water-kerosene model emulsion. The factors influencing the de-emulsification efficiency and the generation site of de-emulsification active component of the strain were also investigated. The similarity of 16SrDNA sequences between strain XH1 and Bacillus mojavensis(DQ993678)was 99%. According to the physiological biochemical test,strain XH1 was preliminarily identified as Bacillus mojavensis. The logarithmic growth,stable phase and decline phase of strain XH1 were determined as 14,18 and 28 h,respectively. The best de-emulsification activity emerged after cultivating for 18h,and the complete de-emulsification was achieved at 24 h. The most favorable incubation conditions for de-emulsification occurred with pH of 6.0 at 30 ℃. The de-emulsification capability of strain XH1 was mainly resulted from extracellular metabolites. The above results indicate that strain XH1 has high de-emulsification efficiency and is potential as a commercial de-emulsifier. 展开更多
关键词 系统发育分析 乳化效率 乳化性能 苏云金芽孢杆菌 16SRDNA序列 菌株 表面活性剂 大庆油田
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