Judul: Sensitivitas Ukuran Amatan Model Autoregresi Fuzzy
Abstrak: The conventional time series modelling method is Autoregressive Integrated Moving Average (ARIMA). ARIMA method is more effective if it is applied in long time periode of observations that at least 50 observations. Tseng on 2001, introduced Fuzzy ARIMA method to deal time series modelling on short time periode of observations. Fuzzy ARIMA combines the advantages of fuzzy logic, ARIMA and fuzzy regression. Considering Tseng’s study the aim of this study is tracing the optimal observation range size when fuzzy ARIMA method is applied at the curent condition. The result of this study indicated that fuzzy ARIMA when the condition of time series data AR(2) with μ=50 and parameter estimation 1=0.600 and 2=0.300 was more sensitive when the observation size less than 20.
Keyword: fuzzy regression, fuzzy logic, fuzzy ARIMA

Judul: Peramalan Tingkat Inflasi dengan Metode Fuzzy Time Series
Abstrak: Inflasi merupakan salah satu indikator yang digunakan untuk menganalisa tingkat perekonomian suatu negara. Peramalan tingkat inflasi penting dilakukan karena hasil yang diperoleh digunakan sebagai salah satu indikator yang dapat memengaruhi kebijakan yang akan dibuat nantinya. Salah satu kebijakan yang menggunakan hasil peramalan ini sebagai salah satu hal yang dapat memengaruhinya adalah kebijakan ekonomi dan kebijakan moneter. Tujuan penelitian ini adalah untuk melakukan peramalan terhadap tingkat inflasi dengan menggunakan metode fuzzy time series serta metode ARIMA, dan membandingkan hasil yang diperoleh. Hasil pendugaan dengan kedua metode memiliki hasil yang mendekati nilai data aktual. Berdasarkan hasil pengukuran kesalahan dengan menggunakan Mean Square Error (MSE), diperoleh bahwa nilai MSE dengan metode fuzzy time series memiliki nilai yang lebih rendah dibandingkan dengan nilai MSE metode ARIMA. Berdasarkan hasil nilai MSE yang didapat, diperoleh hasil bahwa untuk peramalan tingkat inflasi dengan metode fuzzy time series Cheng et al relatif lebih baik dibandingkan dengan metode ARIMA.
Keyword: peramalan, tingkat inflasi, fuzzy time series, ARIMA

Judul: Peptides Hydrolysate Derived from Collagen of Snakehead Murrel (Channa striata) Skin Demonstrate Anti-oxidant and Anti-cholesterol Activities.
Abstrak: Anti-cholesterol and anti-oxidant play crucial role to combat cardiovascular disease (CVD) related to formation of arterial plagues from oxidation of cholesterol. In the past decades, research on bioactive peptides demonstrating anti-cholesterol and anti-oxidant activities have been reported as the alternative drugs. In this study, acid soluble collagen was extracted from the skin of snakehead murrel and employed to induce production of collagenase by Bacillus licheniformis F11.4. The collagenases secreted were in turn purified through AKTA Purifier (ion exchange, DEAE column) and used to produce peptides hydrolysate. The purified enzymes were grouped in two distinct collagenase fractions, designated as fraction D and F. Peptides hydrolysate produced by the fraction D was found to demonstrate HMG-CoA inhibitor activity comparable to pravastatin and limited anti-oxidant activity. Meanwhile, peptides hydrolysate generated using the fraction F demonstrated anti-oxidant activity comparable to BHT (2mM), vitamin C (2mM) and vitamin E (2mM), but limited HMG-CoA activity. Combination of the fraction D and F resulted in substantial HMG-CoA inhibition and anti-oxidant activities.
Keyword: Anti-cholesterol, anti-oxidant, bioactive peptide, collagen, collagenase, snakehead murrel