Penerapan Analisis Survival untuk Menaksir Waktu Bertahan Hidup bagi Penderita Penyakit Jantung

Applying survival analysis in survival data from coroner heart (acute miocard infark) patients is discussed in this short paper. The goal of this research is to determine the treatment that gives a longer survival time. The treatments are the ring treatment, the bypass treatment and the medicine treatment. Data was collected from medical record patients who regularly going to control and check their healthy and conditions to a heart specialist doctor. The sample consists of 90 patients; 30 patients used ring treatment, 30 patients used bypass treatment, and 30 patients used medicine treatment. Survival analysis by using parametric and non parametric estimation are used to estimate the survival time for coroner heart patients using three treatments. The result of this research shows that by using both estimations there is a difference survival time among ring treatment, bypass treatment and medicine treatment. A better medical treatment that gives longer survival time for coroner heart patients is the ring treatment. Key words : survival analysis, parametric estimation, non parametric estimation, survival time

Penerapan Grafik dan Studi Simulasi Hotelling T² Triviat pada Kualitas Parfum Remaja dari Perusahaan “X”

Grafik pengendali merupakan salah satu metode yang digunakan untuk mengendalikan kualitas produk. Makalah ini menjelaskan tentang penerapan grafik Hotelling T² trivariat dengan dipilih α = 0.0027 yang menitik beratkan adanya korelasi signifikan antara karateristik satu dengan karateristik lain yang telah ditetapkan sebagai pengendali kualitas parfum remaja dari perusahaan “X”. Berdasarkan grafik tersebut dapat dibuat perbandingan ellipsoida spesifikasi dengan ellipsoida proses untuk menghitung indeks kemampuan proses yang menghasilkan nilai lebih dari 1. Simulasi dilakukan untuk membuat data baru yang berdistribusi normal trivariat dengan mean dan kovariansi berdasarkan data real. Hasil simulasi memberikan hasil prosentase titik yang di luar kendali mendekati α = 0.0027 untuk ukuran sampel yang cukup besar. Kata Kunci: Grafik Hotelling T² Trivariat, Koefisien Korelasi, Indeks Kemampuan Proses, Simulasi

Pengantar Uji Stabilitas Untuk Model Kompetisi Antara Dua Populasi

The stability analysis for a competition model between two populations is the main topic in this paper. Stability is studied by considering the eigenvalues of system differential equations according to the logistic equations which are developed for two populations. This paper can also be used as an introduction of the qualitative theory through a stability analysis. Additionally, this paper is proposed to the beginners in differential equations

Evaluating the Fitting Performance of AGARCH(1,1), NAGARCH(1,1), and VGARCH(1,1) Models

This study compares the performance of the GARCH(1,1), AGARCH(1,1), NAGARCH(1,1), and VGARCH(1,1) models fitted to real data. The observed real data are the USD exchange rate against IDR in the daily period from January 2010 to December 2017. To identify the superiority and evaluate the performance of those models in capturing the heavy-tailed and skewed character in exchange rate distribution, the return error is assumed to be the Normal, Skew Normal (SN), Skew Curved Normal (SCN), and Student-t distributions. The model's parameters are estimated using the GRG Non-Linear method in Excel Solver and the ARWM method in the MCMC scheme implemented in the Scilab program. Estimation results using Excel's Solver have similar values to the estimates obtained using MCMC, concluding that Excel's Solver has a good ability in estimating the model's parameters. Based on AIC values, this study concludes that the NAGARCH(1,1) model under Student-t distribution performs the best