Judul: Point and Figure Portfolio Optimization Using Hidden Markov Models and its Application on the Stock of Bumi Resources Tbk
Abstrak: The problem of portfolio optimization is to select a trading strategy which maximizes the expected terminal wealth. Since in a real-world market the stocks are traded at discrete random times, we are interested in a time sampling method. The time sampling process obtains sampling of stock price used in point and figure chart. Point and figure chart only displays up or down movements of unbalanced stock price. The basic idea is to describe essential movements of the unbalance stock price using a hidden Markov model. Parameters of this model are transition probability matrices. They are estimated using maximum likelihood method and expectation maximization algorithm. The estimation procedure involves change of measure. The estimation of parameters uses computer algebraic systems on the Mathematica 8.0. The model is then applied to the stock price of Bumi Resources Tbk from January 2nd 2007 until January 31st 2011. The estimated parameters are used to calculate the optimal portfolio using a recursive algorithm. The results of this study show that the discrete hidden Markov model can be applied to describe essential movements of the stock price. The best result gives 93.63% accuracy of the estimate of observation sequence with mean absolute percentage error (MAPE) 3.63% and 5 factors causing the event. The numerical calculation shows that the optimal logarithmic PF-portfolio increases the wealth.
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Judul: Optimasi Alokasi Portofolio Saham Menggunakan Simulated Annealing
Abstrak: Optimation can be regarded as a process to find the best solution by using a systematic procedure. Finance is one of the field of science where optimation is often used, that is investment. Portfolio-making process usually has two steps, the first one is to choose the investment where money are invested and the second one is to determine the allocation for each investment which composed an investment portfolio. Determining the allocation for each investment is not simple as it is often involving high amounts of combination so that doing this process manually consumes too much times and is not efficient. Simulated annealing is one of the method that can be used to solve that problem. This research uses monthly stock’s prices data from 2009-2013, involving 29 companies which are registered on the Jakarta Islamic Index (JII). Based on the result from this research, there are seven stocks which are always included on the portfolio, those seven stocks are CPIN, EXCL, ICBP, KLBF, MAPI, MNCN, and UNVR, with the portfolio’s return’s and risk’s values are 5.63% and 6.79%. Using 24 different datasets, the passive portfolio model’s return’s and risk’s values are 3.06% dan 7% whereas the active portfolio model’s return’s and risk’s values are 5.03% and 6.43%.
Keyword: simulated annealing, portfolio, optimation, metaheuristics, investment

Judul: Enteric Collibacillosis Pada Anak Babi Baru Lahir: Patogenesa dan Perubahan-Perubahan Patologisnya
Abstrak: Diare disebabkan oleh infeksi bakteri Escherichia coli pada anak-anak babi baru lahir yang peka terhadap en terotoksin produk bakteri tersebut. Dikenal sebagai colibacillosis. Patogenesa dari colibacillosis anak babi baru lahir adalah (1) infeksi oleh E. coli patogen, (2) proliferasi E. coli di lumen usus halus, (3) produksi dan pelepasan enterotoksin, dan (4) aktifitas toksin pada usus halus. Dalam proses proliferasi, adanya antigen pili K88 sangat penting karena memungkinkan bakteri perlekatan dengan epitel mucosa usus halus. mengadakan Setelah ko lonisasi dan proliferasi segera toksin dilepaskan. Akti- fitas toksin menginduksi sekresi yang berlebihan dari u- sus sehingga banyak cairan yang dikeluarkan ke lumen usus. Hal ini mengakibatkan banyak cairan dan elektrolit hilang sehingga timbul diare, dehidrasi dan asidosis yang sering menyebabkan kematian. Perubahan-perubahan patologis yang umum adalah dis tensi usus halus, dilatasi lambung dan infark pada kurva- tura mayor. Perubahan-perubahan histologis yang terjadi adalah enteritis hemorrhagica acuta, oedem dan kongesti pembuluh darah di lamina propria, akumulassi leukosit inti polimorf, sel monosit, dan inti sel mengalami piknosis Thrombus pada vena dan degenerasi serta desquamasi sel epitel usus….
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