Judul: Perancangan sistem pakar fuzzy untuk penentuan efektivitas kultivasi cendawan mikoriza arbuskula sebagai pupuk hayati, Design of Fuzzy Expert System for Determination of Cultivation Effectiveness of Arbuscular Mycorrhizal Fungi as Biofertilizer
Abstrak: The use of biofertilizer provides many benefit, including the increased of agricultural production, quality improvement of agricultural product, and reducing the use of artificial fertilizer as well. One of such biofertilizer is Arbuscular Mycorrhizal Fungi (AMF). In cultivation of AMF there are some environment factors which influence cultivation effectiveness, such as soil pH, mean temperature, soil water content, and suitability of host plant. Incompatible factor can give negative impact on AMF cultivation. This research designed an expert system to observe effectiveness value of AMF cultivation based on certain environment factor. This research focused on three AMF specieses, Entrophospora columbiana, Glomus fasciculatum, and Glomus manihotis. This system was built using Fuzzy Inference System (FIS) with four fuzzy parameters: suitability of host plant, soil pH, mean temperature and soil water content. Rules as knowledge base had been built with total 144 rules for each AMF species. Mamdani method is used as inference process. System gives cultivation effectiveness value as output. The effectiveness value shows how effective cultivation process on certain input condition as compared to its best condition. The effectiveness value also divides into four category: not effective, slightly effective, moderately effective, and effective. Based on data verification, system is still unable to gives an accurate effectiveness percentage, altough it is quite good on giving right effectiveness category. To be used in real condition, this system must still be developed further. For example by adding other factors as parameters, such as cultivation time or type of cultivation media.
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Judul: Sistem Pakar Fuzzy Prediksi Efektivitas Respon Tumbuh Fungi Ektomikoriza Pada Tanaman Kehutanan
Abstrak: The growth response effectiveness of ectomycorrhizal fungi is influenced by environmental factors and compatibility with the host plan. An ectomycorrhizal fungi has its own growing characteristics including its level of effectiveness and interaction with the different physiology of the host plant. Thus, experience and expertise are required to make an accurate prediction of the effectiveness of ectomycorrhizal fungi. The objective at this study is designing an expert system model that can predict the effectiveness of ectomycorrhizal fungi quickly, accurately, and easily. The model is developed using a combination of decision trees and adaptive neuro fuzzy inference system (ANFIS). The process is divided into two stages. In the first stage, decision tree with classification and regression tree (CART) algorithm is used as feature selection procedure to select the most important variables. In the last stage, ANFIS is used to predict the growth response effectiveness of ectomycorrhizal fungi. The following process are showing how CART algorithm works, first the process of growing the tree based on the training data, second the process of pruning the tree which is based on the minimum cost-complexity principle. The CART results to identify the structure and parameter of ANFIS . The ANFIS model uses hybrid algorithm to do training and testing. The model performance is assessed by looking the correlation between the testing data with model output and mean absolutely percentage error (MAPE). The correlation model results are 0.998, 0.997, and 0.999 for Ekto1, Ekto2, and Ekto3 respectively. MAPE for Ekto 1 is 1.47%, Ekto 2 is 1.29% and 3.40% for Ekto3. Using the same model, performance tests on mycorrhizal experts are conducted as well. Keywords: expert system, fuzzy, decision trees, CART, ANFIS, effectiveness, ectomycorrhizal.
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Judul: Gelombang Soliter Internal pada Laut Dalam untuk Aliran yang Tunak
Abstrak: Gelombang internal adalah suatu gelombang yang terjadi di bawah permukaan air laut. Gelombang ini muncul karena adanya perbedaan rapat massa di setiap lapisan air laut. Salah satu gelombang internal yang memiliki sifat mempertahankan bentuk dan kecepatannya adalah gelombang soliter internal. Penelitian ini mengkaji gerak gelombang soliter internal pada laut dalam. Penurunan persamaan gerak gelombang internal pada laut dalam menggunakan asumsi bahwa aliran fluida berbentuk tunak. Dalam hal ini persamaan dasar fluida dinyatakan dalam formulasi Lagrange dengan ketinggian fluida dari posisi kesetimbangannya yang merupakan peubah Lagrangenya. Metode yang digunakan untuk menurunkan persamaan gerak gelombang internal adalah metode asimtotik. Dalam metode ini, simpangan gelombang internal dinyatakan dalam uraian asimtotik. Selanjutnya dengan menyeimbangkan faktor taklinear dan dispersi, maka diperoleh persamaan gerak gelombang berupa persamaan Benjamin-Ono (BO). Rumusan gelombang soliter internal dari persamaan BO digunakan untuk mengkaji gerak gelombang soliter pada fluida dua lapisan untuk laut dalam. Hasil yang diperoleh adalah profil gelombang soliter pada setiap kedalaman. Gelombang soliter internal yang memiliki amplitudo terbesar dicapai pada batas antara kedua lapisan fluida, sedangkan di permukaan gelombang relatif kecil.
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