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341.
In this work we have used fuzzy rule-based systems to elaborate a predator–prey type of model to study the interaction between aphids (preys) and ladybugs (predators) in citriculture, where the aphids are considered as transmitter agents of the Citrus Sudden Death (CSD). Simulations were performed and a graph was drawn to show the prey population, the potentiality of the predators, and a phase-plane. From this phase-plane, a classic model of the Holling–Tanner type is fitted and its parameters were found. Finally, we have studied the stability of the critical points of the Holling–Tanner model. 相似文献
342.
343.
In the context of coastal management the aim of this paper is to present the development of a fuzzy model through the application of a Genetic algorithm in order to select the most appropriate set of variables and improve our understanding with a set of rules. The case studied is the chlorophyll response as bioindicator of ecological status in the Northeast coastal upwelling system of Rio de Janeiro state, Southeastern of Brazil. The prediction of the fuzzy model has shown an improved performance when compared to the traditional approaches as Multiple Regression modelling. The results show that the set of inferred rules can assess three different water masses. Despite the increased occurrence of upwelling is observed in spring–summer period and some instability of the model, it is able to forecast some chlorophyll peaks. We conclude that the sampling frequency is crucial to reach a better performance. 相似文献
344.
灰色关联分析法在水质评价中的应用 总被引:1,自引:0,他引:1
提出了等标分极标准的概念,进而利用等标分级标准和待评价水质样本各组分等标污染指数作灰色关联分析,得到一组待评价水质样本对于各级等标分极标准的关联度,按关联度最大将待评价的水质样本归入相应的水质级别中,用该方法对新疆某水库水质进行了评价,通过与模糊综合评判法和灰色聚类法评价结果对比发现:用灰色关联分析法评价水质,既具有模糊综合评判法和灰色聚类法的优点,又弥补了其不完善之处,评价结果比较符合实际状况,且更具有可比性。 相似文献
345.
In this research, a framework combining lean manufacturing principles and fuzzy bow-tie analyses is used to assess process risks in chemical industry. Lean manufacturing tools and techniques are widely used for eliminating wastes in manufacturing environments. The five principles of lean (identify value, map the value stream, create flow, establish pull, and seek perfection) are utilized in the risk assessment process. Lean tools such as Fishbone Diagram, and Failure Mode and Effect Analysis (FMEA) are used for risk analysis and mitigation. Lean principles and tools are combined with bow-tie analysis for effective risk assessment process. The uncertainty inherent with the risks is handled using fuzzy logic principles. A case study from a chemical process industry is provided. Main risks and risk factors are identified and analyzed by the risk management team. Fuzzy estimates are obtained for the risk factors and bow-tie analysis is used to calculate the aggregated risk probability and impact. The risks are prioritized using risk priority matrix and mitigation strategies are selected based on FMEA. Results showed that the proposed framework can effectively improve the risk management process in the chemical industry. 相似文献
346.
《Process Safety and Environmental Protection》2014,92(5):390-405
With the increasing pressures imposed upon industries on the environmental impacts of the manufacturing industry and chemical processes, numerous methodologies have been developed for the quantification, assessment and minimisation of waste and emissions. Meanwhile, methods for the simultaneous maximisation of economic performance within a product life cycle have also been developed. Similarly, various methodologies for screening of process alternatives based on the above factors have also been developed. However, the human lives put at risk in a supply chain constituting a life cycle tend to be overlooked as a factor of assessment, selection and optimisation of the process. Despite having life cycle assessment (LCA) methodologies for environmental assessment, no methodology has been developed for the minimisation of work-related casualties due to the unpredictable nature of workplace accidents. To address this problem, this paper develops a multi-objective optimisation model that utilises realistic statistical data for estimating the best possible pathway. The model results in the least potential fatality directly involved within the product life cycle while simultaneously minimising operating costs throughout the entire life cycle. A case study involving the utilisation of palm-based biomass formed for the production of value-added green products in Malaysia is used to demonstrate the model. 相似文献
347.
《Process Safety and Environmental Protection》2014,92(4):338-345
In this paper, a general procedure to deal with uncertainties in each stage of consequence modeling is presented. In the first part of the procedure, the sources of uncertainty are identified and confirmed by sensitivity analysis for the source term, dispersion, physical effects and consequence analysis. While the second part comprises an application of the fuzzy logic system to each step of the consequence modeling. The proposed procedure is verified by the case study for a pool fire liquefied natural gas (LNG) on water. The results in terms of thermal radiation distances are compared with calculations obtained using the Monte Carlo method and with experimental data. The consequence model based on fuzzy logic approach provides less uncertain and more precise results in comparison to the deterministic consequence model. 相似文献
348.
The relationship between two soil arthropod communities (Coleoptera and Isopoda) in organic and conventional fields was investigated.
Soil arthropods were sampled by pitfall traps, and fuzzy set theory and canonical correspondence analysis (CCA) were used
for their classification. The study was conducted in: (1) two organic and two conventional vineyards, (2) two organic and
two conventional olive groves, and (3) one organic rotation system that involved maize and one conventional maize field. The
species composition (three main fuzzy groups) was affected by the crop species and not by the farming system. The CCA placed
the rare and unique taxa of soil arthropods at the edges of the diagram and grouped most of them together in relation to soil
organic matter and Ca. The same analysis grouped all olive groves and related them to soil organic matter, all vineyards and
related them to soil P and, finally, all maize fields and related them to soil N. 相似文献
349.
大城市郊区土地利用结构类型区评价:以南京市为例 总被引:4,自引:0,他引:4
通过对南京市郊区土地利用结构类型区划分指标的模糊聚类分析,将南京城郊划分为8个类型区,并比较分析了各个类型区的土地利用特征及集约经营程度,土地利用效益,最后指出:为了优化配置郊区土地资源,南京市郊区土地利用必须采取因地制宜,综合利用,集约经营,增加投入,保护耕地,持续利用的措施。 相似文献
350.
This article presents the design of a fuzzy decision support system (DSS) for the assessment of alternative strategies proposed for the restoration of Lake Koronia, Greece. Fuzzy estimates for the critical characteristics of the possible strategies, such as feasibility, environmental impact, implementation time, and costs are evaluated and supplied to the fuzzy DSS. Different weighting factors are assigned to the critical characteristics and the proposed strategies are ordered with respect to the system responses. The best strategies are selected and their expected impact on the ecosystem is evaluated with the aid of a fuzzy model of the lake. Sensitivity analysis and simulation results have shown that the proposed fuzzy DSS can serve as a valuable tool for the selection and evaluation of appropriate management actions.
Note: This version was published online in June 2005 with the cover date of August 2004. 相似文献