Judul: Uji karakteristik water absorbent pati singkong serta pengaruhnya terhadap tanaman cabai pada tanah bertekstur pasir
Abstrak: Tin mine tailing in Bangka Belitung island covers significantly large area. Unfortunately, this tailing contain very high sand (>90%) but very low clay (<5%) and very low organic matter (<1%), that is has very low water retention ability. Common effort to overcome low water retention problem is by using intensive irigation. However, intensive use of irigation tends to be inefficient. To reduce the intensity of irigation, the use of water absorbent is presently began widely introduced, one of them is SWA (Super Water Absorbent) Cassava Starch. A study to examine the characteristics of SWA Cassava Starch and observe its effect to chilli plants in sand-textured soils was conducted in a greenhouse. The study consisted of two series of experiments. First, evaluation of SWA Cassava Starch (in swelling condition) degradability based on the decrease in the weight of SWA (swelling) toward the time. Second, evaluation of the effect of water absorbent on chili plant growth using Completely Randomized Design with three treatment factors namely (1) Water absorbent consisting of 8 standard; (2) sand soil consisting of 2 standard, and (3) Watering consisting of 2 standard. SWA Cassava Starch in applied in wet method before which SWA is soaked in water until it reaches equilibrium. Result of the experiments showed that SWA Cassava Starch (in swelling condition) degradability tend to be the same on the Regosol soil or sand tailings simulation soil. Second experiment indicated that in general water absorbent had no significant effect on chili plants growth, eventhough SWA Cassava Starch treatment with a dose of 0.1 g/kg in combination with chitosan tends to give a better effect. Chili plants growth at “a without watering treatment” with SWA treatment have a shorter life cycle compared to “once a week watering treatment”.
Keyword: Bogor Agricultural University (IPB), sand soil, chili plants, SWA cassava starch

Judul: Pengaruh SWA (Super Water Absorbent) Pati Singkong Terhadap Sifat Retensi Air Tanah
Abstrak: The development of dry-land agriculture often face some constraints, especially when it is related to water needs which is depending on rainwater. Global climate change, that occurs lately has made rainfall patterns become more erratic and less predictable. Therefore, new technology that could help maintaining soil water content is needed to ensure that water availability for plant growth is still sufficient. SWA (Super Water Absorbent) cassava starch is one of a technology that can be used for this purpose. This study was aimed to assess the effect of SWA cassava starch and its comparison to the other water absorbent, for maintaining soil water retention on two different soil textures (clay and sandy clay). The results showed that addition of SWA cassava starch was not significantly different from the other soil water absorbent for maintaining soil water retention. SWA cassava starch performance at clay textured soil was better than sandy clay-textured soil.
Keyword: 

Judul: Estimating Parameter and the Convergence of Parameter Estimator of Poisson Hidden Markov Model
Abstrak: Model hidden Markov terdiri dari sepasang proses stokastik yaitu proses observasi dan proses yang memengaruhi observasi. Proses stokastik yang memengaruhi observasi ini diasumsikan membentuk rantai Markov dan tidak diamati. Model Poisson hidden Markov (MPHM) adalah salah satu model hidden Markov diskret dan proses observasinya jika diketahui proses yang memengaruhinya diasumsikan menyebar Poisson., A hidden Markov model (HMM) consists of a pair of stochastic processes, that is the observation process and process that affected observation. The stochastic process which causes this observation is assumed to form a Markov chain and is not observed. Poisson hidden Markov models (PHMM) is one of the discrete HMM and the observation process given the cause is assumed having a Poisson distribution.
Keyword: Poisson hidden Markov model, Forward-Backward algorithm, Expectation Maximization algorithm