Solving Fuzzy Multi-Objective Linear Programming Problem by Applying Statistical Method

In this paper, the statistical averaging method and the new statistical averaging methods have been used to solve the fuzzy multi-objective linear programming problems. These methods have been applied to form a single objective function from the fuzzy multi-objective linear programming problems. At first, a numerical example of solving fuzzy multi-objective linear programming problem has been provided to validate the maximum risk reduction by the proposed method. The proposed method has been applied to assess the risk of damage due to natural calamities like flood, cyclone, sidor, and storms at the coastal areas in Bangladesh. The proposed method of solving the fuzzy multi-objective linear programming problems by the statistical method has been compared with the Chandra Sen’s method. The numerical results show that the proposed method maximizes the risk reduction capacity better than Chandra Sen’s method.

近25a来天津市海河干流水质的演变特征

选取海河干流天津市区段1986—2009年的5项重要水质指标(氯化物、DO、COD、BOD和氨氮),采用距平法、LOWESS平滑法、Mann-Kendall检验法和Sen方法对其水质变化趋势及特点进行分析,研究近25 a来海河干流水质的演变特征。结果表明:①这4种方法及其结合为水质趋势分析和水质管理提供了一种有效手段,不同方法之间可相互验证、相互补充,共同反映水质的演变规律;②近25 a来,海河干流大致满足其为"备用饮用水源地,工业水源地,市区景观娱乐用水"的水功能区划,5项指标中仅COD呈显著上升趋势,上升速率为0.13 mg/(L.a),氯化物含量和BOD呈上升趋势,DO和氨氮含量呈下降趋势,但都不具有显著趋势。海河干流水质总体相对稳定,没有明显变化。

衢江水沙变化趋势分析

以衢州水文站以上流域为研究区域,基于衢江衢州水文站1958—2006年径流量和输沙量序列,采用Mann-Kendall趋势检验法、Sen's坡度检验法、累加滤波器法与双累积曲线法,探讨近50年来衢江径流量和输沙量的变化趋势以及水沙关系的变化特征,并分析引起水沙序列变化的可能影响因素。结果表明:衢江年径流量无明显的变化趋势,而枯水月份(8月至次年1月)的径流量呈现显著增大的趋势,丰水月份中5月的径流量则呈现减小的趋势。输沙量变化趋势较为明显,自1980年以来衢江输沙量呈显著减小的趋势。从降水情况、水库拦沙和水土流失的治理状况等方面分析了引起衢江水沙变化的原因,提出衢江流域内水库所发挥的"蓄丰补枯"补水调节作用可能造成了径流量的变化,而水库建设与水土保持措施可能是流域输沙量减小的重要原因。