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浅析建筑工程造价管理中的不确定因素及控制措施 被引量:1
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作者 陈俊杰 《城市建筑》 2016年第2期150-150,152,共2页
对建筑工程的造价进行有效管理是指在工程的建设过程中对其投资费用和价格进行的管理.建筑工程的造价管理能够确保投资预期目标的实现,在对规划进行拟定、对方案进行设计的前提下,对建筑工程造价进行预测、监控、确定有着重要的意义.被... 对建筑工程的造价进行有效管理是指在工程的建设过程中对其投资费用和价格进行的管理.建筑工程的造价管理能够确保投资预期目标的实现,在对规划进行拟定、对方案进行设计的前提下,对建筑工程造价进行预测、监控、确定有着重要的意义.被结合笔者多年的实践经验,对目前建筑工程造价中存在的问题进行了分析,并在此基础上提出了科学的措施. 展开更多
关键词 建筑工程 造价过程 不确定性信息分析
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Quantitative comparison of similarity measure and entropy for fuzzy sets
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作者 JUNG Dong-yean CHOI Jung-Wook +1 位作者 PARK Wook-Je LEE Sang-Hyuk 《Journal of Central South University》 SCIE EI CAS 2011年第6期2045-2049,共5页
Comparison and data analysis with the similarity measures and entropy for fuzzy sets were carried out. The distance proportional value between the fuzzy set and the corresponding crisp set was considered by the fuzzy ... Comparison and data analysis with the similarity measures and entropy for fuzzy sets were carried out. The distance proportional value between the fuzzy set and the corresponding crisp set was considered by the fuzzy entropy. The relation between the similarity measure and the entropy for fuzzy set was also analyzed. The fuzzy entropy was reformulated as the dissimilarity measure. Furthermore, crisp set having the minimum uncertainty with respect to the corresponding fuzzy set was also proposed. Finally, derivation of a similarity measure from entropy with the help of total information property was derived. A simple example shows the relation between similarity measure and fuzzy entropy, in which the summation of similarity measure and fuzzy entropy represents a constant value. 展开更多
关键词 similarity measure fuzzy entropy minimum uncertainty quantitative comparison
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Uncertainty and Sensitivity Analyses for Modeling Long-Term Soil Organic Carbon Dynamics of Paddy Soils Under Different Climate-Soil-Management Combinations
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作者 QIN Fal ZHAO Yongcun +2 位作者 SHI Xuezheng XU Shengxiang YU Dongsheng 《Pedosphere》 SCIE CAS CSCD 2017年第5期912-925,共14页
Reporting modeling results with uncertainty information can benefit decision making by decreasing the extent that variability exerts a disproportionate influence on the options selected. For making decisions with more... Reporting modeling results with uncertainty information can benefit decision making by decreasing the extent that variability exerts a disproportionate influence on the options selected. For making decisions with more confidence, the uncertainty interval should be as narrow as possible. Here, the soil organic carbon (SOC) dynamics of the major paddy soil subgroup from 4 different paddy field regions of China (located in 4 counties under different climate-soil-management combinations) were modeled using the DeNitrification- DeComposition (DNDC) model for the period from 1980 to 2008. Uncertainty intervals associated with the SOC dynamics for these 4 subgroups were estimated by a long-term global sensitivity and uncertainty analysis (i. e., the Sobolt method), and their sensitivities to 7 influential factors were quantified using the total effect sensitivity index. The results, modeled with high confidence, indicated that in the past 29 years, the studied paddy soils in Xinxing, Yixing, and Zhongjiang counties were carbon (C) sinks, while the paddy soil in Helong County was a C source. The 3 C sinks sequestered 12.2 (5.4, 19.6), 17.1 (8.9, 25.0), and 16.9 (-1.2, 33.6) t C ha-1 (values in the parentheses are the 5th and 95th percentiles, respectively). Conversely, the C source had a loss of -5.4 (-14.2, 0.06) t C ha-1 in the past 29 years. The 7 factors, which changed with the climate-soil-management context, exhibited variable influences on modeled SOC. Measures with potential to conserve or sequestrate more C into paddy soils, such as incorporating more crop residues into soils and reducing chemical fertilizer application rates, were recommended for specific soils based on the sensitivity analysis results. 展开更多
关键词 carbon loss carbon sequestration carbon sink carbon source DeNitrification-DeComposition model fertilizer appli-cation influential factors residue incorporation Sobol~ method
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A New Hybrid Reliability Index Definition and Its Application to the Structure Buckling Reliability Analysis of Supercavitating Projectiles
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作者 周凌 李志涛 +1 位作者 韩景壮 张楠 《Journal of Shanghai Jiaotong university(Science)》 EI 2016年第4期467-471,共5页
As structure buckling problems easily arise when supercavitating projectiles operate with high underwater velocity, it is necessary to perform structure buckling reliability analysis. Now it is widely known that proba... As structure buckling problems easily arise when supercavitating projectiles operate with high underwater velocity, it is necessary to perform structure buckling reliability analysis. Now it is widely known that probabilistic and non-probabilistic uncertain information exists in engineering analysis. Based on reliability comprehensive index of multi-ellipsoid convex set, probabilistic uncertain information is added and transferred into non-probabilistic interval variable. The hybrid reliability is calculated by a combined method of modified limit step length iteration algorithm(MLSLIA) and Monte-Carlo method. The results of engineering examples show that the convergence of MLSLIA is better than that of limit step length iteration algorithm(LSLIA). Structure buckling hybrid reliability increases with the increase of ratio of base diameter to cavitator diameter, and decreases with the increase of initial launch velocity. Also the changes of uncertain degree of projectile velocity and cavitator drag coefficient affect structure buckling hybrid reliability index obviously. Therefore, uncertain degree of projectile velocity and cavitator drag coefficient should be controlled in project for high structure buckling reliability. 展开更多
关键词 supercavitating projectile structure buckling hybrid reliability modified limit step length iteration algorithm (MLSLIA) Monte-Carlo method
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