Judul: Wavelet and ARIMA Analysis in Forecasting Gold Price of PT Antam Tbk Indonesia
Abstrak: Peramalan adalah suatu proses memperkirakan secara sistematis tentang kemungkinan yang akan terjadi di masa depan berdasarkan informasi masa lalu. Data deret waktu adalah urutan pengamatan berdasarkan waktu. Analisis data deret waktu dapat menggunakan beberapa metode, yaitu metode analisis domain waktu seperti ARIMA, atau analisis domain frekuensi seperti wavelet. Dalam analisis ARIMA, stasioneritas data merupakan salah satu faktor yang harus dipenuhi. Wavelet adalah fungsi matematis yang memotong data ke dalam beberapa komponen yang berbeda dan mempelajari setiap komponen berdasarkan resolusi yang sesuai dengan beberapa skala. Data asli didekomposisi untuk menghasilkan koefisien wavelet dan koefisien skala yang kemudian digunakan untuk memprediksi data pada periode berikutnya., Forecasting is an estimation of a systematic process which is most likely to occur in the future based on past informations. Time series data are sequence of observations, which are ordered in time. Analysis of time series data can use several methods, namely a time domain analysis method such as ARIMA, or frequency domain analysis such as wavelet. In ARIMA analysis, stationarity of data is one factor that must be met. Wavelet is a mathematical function that cut the data into different components and study each component with a resolution corresponding to some scales. The original data are decomposed to produce wavelet coefficients and scale coefficients, which are then used to predict the time series in the next period.
Keyword: forecasting, wavelet, time series, ARIMA

Judul: Peramalan Harga Saham PT Garuda Indonesia Saat Covid-19   dengan Menggunakan Model ARIMA
Abstrak: Avlation is one of the industries that has an impact on the restriction system to prevent the spread of the Covid-19 virus. Therefore, investors find it difficult to assume whether making an investment at the time of restriction will bring future profits or losses. To overcome this, forecasting is needed. One method that is often used is the ARIMA model. The data used is the daily stock price of PT Garuda Indonesia from January 1, 2020 to April 26, 2021. The most suitable model is ARIMA(2,1,2) with a MAPE around 4.3%. After forecasting for the next 10 periods, the MAPE is obtained at around 0.78%, this means that the error rate is quite low., Penerbangan merupakan salah satu industri yang berdampak pada saat sistem pembatasan untuk mencegah penyebaran virus Covid-19. Oleh karena itu, investor merasa kesulitan untuk mengasumsikan apakah melakukan investasi pada saat pembatasan akan mendatangkan keuntungan atau kerugian di masa yang akan datang. Untuk mengatasi hal tersebut perlu dilakukan peramalan. Salah satu metode yang sering digunakan adalah Model ARIMA. Data yang digunakan adalah data saham harian PT Garuda Indonesia dari 1 Januari 2020 sampai dengan 26 April 2021. Model yang paling sesuai adalah ARIMA(2,1,2) dengan MAPE sebesar 4.3%. Setelah dilakukan peralaman untuk 10 periode yang akan datang diperoleh MAPE sebesar 0.78%, artinya tingkat kesalahan yang dihasilkan cukup rendah.
Keyword: ARIMA, Covid-19, forecasting, avlation.

Judul: Light Microscope Study of ConnectiveTissue in The Spleen of Common Rousette Bat (Rousettus amplexicaudatus)
Abstrak: The spleen is the largest lymphoid organ. As a secondary lymphoid organ, in addition to its immune function, the spleen also has functions as blood filtration, storage, and hematopoiesis. The spleen has different morphologies between species that support different physiological functions, one of which is the difference in the structure of the capsule and trabeculae. Capsule and trabeculae of the spleen generally consist of connective tissue and smooth muscle. The thickness of smooth muscle composed together with connective tissue in the capsule and trabecula determines the function of the spleen that is divided spleen into three storage, defense, and intermediate. Bats are the reservoir of various zoonotic diseases. Bats are thought to have unique immune systems compared to other mammals but the characteristics of its immune organs such as the spleen have never been studied before. This study was conducted to examine the characteristics of capsulae and trabecula of the Common Rousette (Rousettus amplexicaudatus).
Keyword: