Judul: Optimization of Total Flavonoid Extraction and Antioxidant Activity of Gandarusa Leaf Using Two Half Factorial.
Abstrak: Gandarusa (Justicia gendarussa Burm.F.) memiliki berbagai kandungan senyawa bioaktif dengan kandungan antioksidan tinggi yang umumnya dimanfaatkan sebagai obat herbal. Penelitian ini bertujuan untuk mengetahui kombinasi ekstraksi pelarut terbaik serta pengaruh terhadap beberapa faktor yaitu pH, konsentrasi pelarut, waktu, suhu, serta rasio antara cairan dan padatan menggunakan metode Two-half factorial terhadap kadar flavonoid dan antioksidan pada tanaman gandarusa. Hasil penelitian optimasi ekstraksi metode two half factorial menunjukan bahwa kadar total flavonoid dipengaruhi oleh faktor dengan kontribusi tertinggi yaitu interaksi konsentrasi etanol dan pH. Aktivitas antioksidan DPPH dipengaruhi oleh faktor interaksi suhu, konsentrasi etanol, dan pH serta FRAP dipengaruhi oleh faktor interaksi rasio cairan/padatan, suhu, konsentrasi etanol dan pH. Formula rasio cairan/padatan 10 mL/g, suhu 80°, konsentrasi etanol 80%, dan pH 6 merupakan kondisi yang optimum dalam ekstraksi senyawa flavonoid dan aktivitas antioksidan dengan nilai desirability sebesar yaitu 0,82., Gandarusa (Justicia gendarussa Burm.F.) has various bioactive compounds with high antioxidant content which is commonly used as herbal medicine. This study aimed to determine the best solvent extraction combination and the effect of several factors, namely pH, solvent concentration, time, temperature, and the ratio between liquid and solid using the Two-half factorial method on flavonoid and antioxidant levels in gandarusa plants. The results of the extraction optimization research using the two-half factorial method show that the total flavonoid content was influenced by the factor with the highest contribution, namely the interaction of ethanol concentration and pH. DPPH antioxidant activity was influenced by the interaction factors of temperature, ethanol concentration, and pH and FRAP was influenced by the interaction factors of liquid/solid ratio, temperature, ethanol concentration and pH. The liquid/solid ratio formula of 10 mL/g, temperature 80°, ethanol concentration 80%, and pH 6 was the optimum condition in the extraction of flavonoid compounds and antioxidant activity with a desirability value of 0.82.
Keyword: antioxidant, flavonoid, gandarusa, optimization

Judul: Optimization of Extraction for Total Phenolics and Highest  Antioxidant Capacity in Gandarusa Using Two-Level Half Factorial Design
Abstrak: Gandarusa (Justicia gendarussa Burm. f.) telah digunakan sebagai obat tradisional dan dilaporkan memiliki senyawa fitokimia dan aktivitas antioksidan yang tinggi. Penelitian ini bertujuan untuk mengukur pengaruh perbedaan kondisi ekstraksi berdasarkan rasio cairan terhadap padatan, suhu, konsentrasi pelarut, waktu, dan pH tanaman gandarusa dengan two level half factorial design terhadap produksi metabolit sekunder dan kapasitas antioksidannya. Sampel diekstraksi sesuai dengan desain two level half factorial. Kandungan fenolik, kapasitas antioksidan DPPH dan FRAP tertinggi didapat oleh run-13 berturut-turut sebesar 28,15 mg GAE/g, 54,19 μmol TE/g, dan 218,73 μmol TE/g. Desain two level factorial digunakan untuk menentukan faktor yang signifikan terhadap ekstraksi kadar fenolik total, serta kapasitas antioksidan DPPH dan FRAP. Faktor suhu berperan signifikan (< 0,05) terhadap kadar fenolik total. Sedangkan pada kapasitas antioksidan DPPH didapatkan bahwa faktor cairan terhadap padatan dan pH berperan signifikan (< 0,05). Pada FRAP didapatkan bahwa faktor cairan terhadap padatan menjadi faktor yang berperan signifikan (< 0,05). Kata kunci: antioksidan, factorial, gandarusa, cairan terhadap padatan, suhu, Gandarusa (Justicia gendarussa Burm. f.) is often used as a traditional medicine and is reported to contain high levels of phytochemical compounds and antioxidant activity. This study aimed to measure the influence of different extraction conditions based on liquid to solid ratio, temperature, solvent concentration, time, and pH of gandarusa plant on the production of secondary metabolites and antioxidant capacity using a two-level half factorial design. Samples were extracted according to the two-level half factorial design. The highest phenolic content, DPPH and FRAP antioxidant capacity were obtained from run 13, with values of 22.75 mg GAE/g, 43.36 μmol TE/g, and 166.72 μmol TE/g, respectively. A two-level factorial design was used to determine the significant factors affecting the extraction of total phenolic content, DPPH antioxidant capacity, and FRAP antioxidant capacity. Temperature was found to have a significant effect (<0.05) on the total phenolic content. Meanwhile, for DPPH antioxidant capacity, the liquid to solid ratio and pH was found to be the significant factor (<0.05). In FRAP, it was found that the liquid to solid factor was a significant factor (<0.05). Keyword: antioxidant, factorial, gandarusa, liquid to solid, temperature
Keyword: antioxidant, factorial, gandarusa, liquid to solid, temperature

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