Pi型及Dsig型隸屬函數應用於西北颱降雨之分析比較

Application of Pi-shaped and Dsig-shaped Membership of Fuzzy Function to Rainfall Analysis and Comparison for Northwestwardly Typhoons

李珮琪(Pei-Chi Lee)

指導教授 ： 邱金火

中原大學/工學院/土木工程研究所/碩士(2009年)

https://doi.org/10.6840/CYCU.2009.00776

摘要

本研究選用pi型隸屬函數及dsig型隸屬函數當輸入函數，將影響西北颱降雨量的五個氣象因子－平均相對濕度、暴風半徑、測站最低氣壓、颱風中心與測站之距離、颱風移動速度，作為五個輸入變數，並建立模糊隸屬函數，來模擬推估西北颱的降雨量，進而與前人所用之四種隸屬函數-三角形隸屬函數、梯形隸屬函數、鐘形隸屬函數、高斯曲線隸屬函數做比較，以分析比對不同隸屬函數推估值之誤差。其建構流程為先將輸入變數値做模糊化的轉換，利用MATLAB中之ANFIS程式做模糊類神經網路演算建立模糊資料庫，建立資料庫後，將演算結果解模糊化轉換輸出，以推估各測站之降雨量，再與各測站之實際降雨量作檢驗，分析比較其學習模擬成果。
颱風之模組建構以西元1958年至2005年中央氣象局之基本颱風降雨資料，藉颱風降雨資料作模糊演算及分析，其結果可看出本研究所比較之六種隸屬函數於颱風降雨量之訓練結果整體趨勢相似。推估階段的颱風預估雨量上，在基隆、台北、宜蘭、台中等位於台灣北部各地及中央山脈西側之測站其誤差皆屬可接受範圍內，此結果可供未來西北颱降雨預報之參考。

關鍵字

模糊隸屬函數

並列摘要

In this research, the five factors affecting rainfall of northwestwardly typhoons were selected as the input membership of the fuzzy function. They are the average relative humidity, the radius of typhoons, the minimum atmospheric pressure at station, the distance between typhoon center and observation station, the typhoon velocity. These variables were considered to have Pi-shaped and Dsig-shaped distribution from which the membership of the fuzzy function were set up to predict the rainfalls of northwestwardly typhoons. Fuzzification transfers the input data and creates the fuzzy database by using the method of the neural nets and its computation program MATLAB/ANFIS. After the database was set up, the predicted rainfalls can be obtained by the antifuzzification. The estimated rainfalls were compared with the observed rainfalls of each station. From these comparisons, the learning effects were analyzed until the minimum errors were obtained.
Use the typhoon data from the Central Weather Bureau during the period from years 1958 to 2005, to make a fuzzy calculation and analysis by using rainfall data. From the results in the learning stage of the six membership functions, the over-all trends of the estimated rainfalls for each station were similar, and the accuracies were feasible. The estimated rainfalls predicted in the stations of Keelung, Taipei, I-Lan, Taichung, located at the Northern area, as well as in the stations located in the west side of Taiwan Central Mountains are in a acceptable range. The results of this study can be used as a reference for the rainfall prediction for the northwestwardly typhoons in the future.

並列關鍵字

membership of fuzzy

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