Judul: Pemodelan Frekuensi Petir di Bogor Menggunakan Pendekatan Logika Fuzzy
Abstrak: Guinness Book of Records in 1989 as indicated in the Antara News article (2013) showed that Bogor is one of the areas with the highest potential for lightning in the world. However, the recording devices that count frequency lightning are repeatedly damaged. Hence, the records are badly documented. This study was conducted to model the frequency of lightning in Bogor using fuzzy logic approach. The method used is the Mamdani method consists of four stages: fuzzification, implication function application, aggregation of rules, and defuzzification. The formed model took the following inputs: air temperature, air humidity, wind speed, rainfall and evaporation. The output data of this model is the frequency of lightning. The results indicate 81 rules model of lightning frequency. Fuzzy modelling accuracy could be indicated by the mean value of the absolute percentage error (MAPE) of 17.2%.
Keyword: Bogor Agricultural University (IPB), MAPE, fuzzy modelling, lightning

Judul: Arima Model For Monthly Temperature And Rainfall In Bogor
Abstrak: average condititon among items from many components of climate system. There arc many factors determine the differences of the climate among one place to another place in the world. The climate•s components very often used to define the climate in some place arc the temperature and the minfal!. The damages caused by climate (such as: drought, flood, global wanning) actually can be avoided if we have known climate prediction. such as periodicity. rainfall prediction and temperature prediction. Bogor that is known as "'rain city" is very interesting to investigate like what the pattern of it '5 rainfall and temperature. The temperature in Bogor have periodicity of 12 monthly and the rainfall have periodicity of 36 monUlly (3 yearly). The model for the montilly temperature in Bogar is as [ollOlr: X, = 0,8254X,.! + X,." - 0.8254X'.13 +c, - 0.4186c'.1 - 0.9475c,." + 0.3966c'.13. The model for the lllontIlly rainfall in Bogar is as follow: X, = 0.8455X'~6+0.1525X'.72"'" +0.1318£'.1 -0.8567£,.",+0.1129£'-37. From these both satisfactory models we established. we can explore and analyse lImy strong the PHst temperature correlates to the present temperature. And from these model we can also do forecasting. Key words: Stationarity. Ergodicity. Autocorrelation Function. ARIMA (Auto Regressive Integrated Moving Average) ModeL Q Box-Pierce Test. Forecasting.
Keyword: 

Judul: Karakteristik Carboxymethyl Chitosan Dengan Variasi Konsentrasi NaOH
Abstrak: Carboxymethyl chitosan is chitosan derivative product obtained from chemical modification. CMCh were made by alkalization process and carboxymethylation process. Factors that affect CMCh characteristics were excess sodium hydroxide in alkalization process, ratio between chitosan and monochloroacetic acid, and carboxymethylation temperature. The objectives of this research were to study the NaOH effect to CMCh characteristics, to learn process of making CMCh, to set the proper concentration of NaOH, and to analyze CMCh characteristics. CMCh yields were 110.72%-114.22%. CMCh pH value were 3.74-4.31. The optimum NaOH concentration to obtain the best CHCh was 10 M. Percentage of CMCh moisture content was 10.70%-11.42%. Ash content and nitrogen content of CMCh were 0.49%-0.50% and 4.52%-4.81%. CMCh viscousity was 8.25 cps. Percentage of CMCh solubility was 61.61%-91.50%. The different functional groups from chitosan which observed in CMCh were C=O group, CH group from alkene functional group, C−O group, and C−O−C group.
Keyword: solubility., functional group, CMCh characteristics, chitosan, carboxymethyl chitosan