Judul: Penyusunan Composite Index Indonesia 1983-2000 Dan Pemodelan Menggunakan Msar (Markov Switching Autoregressions)
Abstrak: Kondisi perekonomian Indonesia seCaI"a agregat-dapat digambarkan· oleh composite index, yaitu suatu index yang merupakan gabungan dari beberapa indikator. Composite index terdiri dad coincident index (el) yang menggambarkan kondisi perekonomian sekarang dan leading index (LI) yang menggambarkan arah pergerakan perekonomian dalam beberapa peri ode ke depan. Pemodelan composite index tidak dapat menggunakan model AR(P) biasa, karena variabel ekonomi dan keuangan Indonesia mengalami perubahan perilaku yang dramatis yang antara lain disebabkan oleh krisis ekonomi. Perubahan perilaku tersebut dapat dianggap dipengaruhi oleh suatu peubah acak tidak teramati s, bersifat diskret yang biasanya disebut sebagai state/regime di mana PToses tersebut berada pad a waktu t.
Keyword: 

Judul: Time Series Data Analysis with Heterogen and Asymmetry Error Variance : Jakarta Composite Index Study for 1999-2008.
Abstrak: Time series data at financial area has value experiencing fluctuate from time to time. This fluctuation results its conditional variance is becoming not constant. So modelling with model ARIMA cannot be applied by assumption of homogeneity of variance is not fufilled. One of way of overcome it is with simultaneously modeling mean function and variance function. The model is recognized as Generalized Autoregressive Conditional Heteroscedasticity (GARCH). Some data financial shows existence of negative relationship between value changes return wit h movement of its volatility. Existence of impairment return has influence larger ones to movement of its volatility. Exponential-GARCH (EGARCH) model can overcome the asymmetric problem with modeling conditional variance as function of log-linear. So conditional variance value predicted negativity will never. Jakarta Composite Index (JCI or IHSG) be one of indicators applied by government in taking policy in the field of chartered investment counsel. Besides government assumes the importance of stock market alternatively defrayal besides banking. A real big fluctuation happened in stock exchange, because every transaction is noted with small time scale so that value change happened so quickly. At this case assumption of homogeneity of variance is not fufilled. At stock exchange also shows existence of asymmetric influence. Hence applied model EGARCH in modeling daily value of JCI (IHSG). Chosen EGARCH model is MA(1)-EGARCH(1,1). EGARCH Model very good in modeling daily value of JCI (IHSG), but have not yet enough good to forecasting value JCI (IHSG ) which will come. Besides forecast to daily value of JCI (IHSG), modelling of variance function also yields forecasting to its conditional variance. Forecast of conditional variance hardly good for asset holder in seeing behavior of movement of JCI (IHSG ) and calculate level of risk holds a leg asset in the future.
Keyword: 

Judul: Detoxification of Cassava’s Acid Hydrolyzate by Activated Carbon Method for Bioethanol Production
Abstrak: Cassava is one of natural resources for carbohydrate that also available for bioethanol production. Starch and fibers hydrolysis maybe conducted on acid condition. The restriction in acid hydrolysis is 5-hydroxymethyl furfural (HMF) and furfural formation, which inhibit yeast fermentation. This study applied two stages of detoxification, which are overliming and activated carbon adsorption methods for lowering HMF and furfural concentrations. In order to obtain tolerable amount in sugar solution, detoxification by activated carbon adsorption was done by concentration of 1%, 2.5%, 5% and 10% and duration of contact are 30 45 and 60 minutes. The results showed that overliming method decreased HMF and furfural concentrations 34.38% and 60.81%, respectively. Overliming followed by 5% activated carbon adsorption for 30 minutes produced the best sugar solution which has a lower HMF and furfural concentrations by 72.03% and 89.11%, respectively. Adsorption constants of HMF and furfural by 5% activated carbon were 0.044 g/min and 3,7 x 10-5 g/min, respectively. The concentration of ethanol produced was 5.00% (b/v) or 63.22% higher than obtained from detoxification by neutralization (NH4OH) which produced ethanol only 3.06%.
Keyword: