Jurnal Ilmiah Sains

Comparison of Stock Prediction Using ARIMA Model with Multiple Interventions of Step and Pulse Functions

Muh. Qodri, Utriweni Mukhaiyar, Vira Ananda, Siti Maisaroh — Sun, 17 Mar 2024 00:00:00 +0800

Stock price predictions based on technical analysis using historical data help investors determine the optimal time to buy or sell shares with the aim of achieving maximum profits. The aim of this research is to compare the results of Kimia Farma's share price predictions using the ARIMA model with intervention analysis of two variables at once, namely the pulse function and the step function. This is the novelty of this research. The data used in this research is daily data on Kimia Farma shares from the period 16 April 2018 to 14 April 2023. The best model produced is ARIMA (0,1,1) with intervention, shown by a MAPE value of 0.3356% and an RMSE of 0.3356%. 4.03. Kimia Farma's share price prediction for the next five days is 906.5548; 905.7875; 905.0206; 904.2542; 903.4882 rupiah. An increase in share prices occurred after the intervention in the period 15 April 2023 to 19 April 2023.

Keywords: ARIMA; intervention model; step and pulse function; kimia farma

Assimilate Partition of Potato (Solanum tuberosum L.) as Response to Combination of Paclobutrazol and Nitrogen

Tue, 09 Apr 2024 00:00:00 +0800

Increasing the productivity of potato (Solanum tuberosum L.) can be done by increasing biological production (biomass) and the ability to convert (partition) assimilate/photosynthate into economic results (tubers). The aim of this research is to find a better combination of paclobutrazol (PBZ) application and nitrogen (N) fertilization for tuber partition assimilate of potato. The experiment was conducted in Randomized Block Design (RBD) with three replications. The treatment was consists of nine combinations of PBZ treatments and N fertilization as follows: 1) 3 kg PBZ/ha + 200 kg N/ha, 2) 3 kg PBZ/ha + 250 kg N/ha, 3) 3 kg PBZ/ha + 300 kg N/ha, 4) 3,5 kg PBZ/ ha + 200 kg N/ha, 5) 3,5 kg PBZ/ha + 250 kg N/ha, 6) 3,5 kg PBZ/ha + 300 kg N/ha, 7) 4 kg PBZ/ha + 200 kg N/ha, 8) 4 kg PBZ/ha + 250 kg N/ha, 9) 4 kg PBZ/ha + 300 kg N/ha. The research results showed that at the beginning of growth up to 42 DAP (day after plan), the assimilate (dry material) was directed towards stem and leaf (shoot) growth. Next, at 56 DAP to 84 DAP the assimilate is allocated for tuber growth. The combination of 4 kg PBZ/ha + 200 kg N/ha produces the largest tuber weight

Keywords: Potato (Solanum tuberosum L); nitrogen; paclobutrazol; partition assimilate

Susceptible-Infected-Recovered Model of Mathematics Anxiety Behavior on Students' Mathematics Study Results at Aquino Catholic High School Amurang

Thu, 11 Apr 2024 00:00:00 +0800

This study aims to see the spread of mathematics anxiety behavior on the results of students' mathematics studies at Aquino Catholic High School Amurang by using the SIR (Susceptible-Infected-Recovered) mathematical model. A total of 88 samples were collected and categorized into three groups based on predetermined criteria. These groups consisted of 47 students categorized as susceptible, 27 as infected, and 14 as recovered. The parameters in this study measure the rate of change within these three groups over a 365-day period, equivalent to one year. Two equilibrium points are obtained that can interpret populations free from math anxiety behavior or endemic math anxiety behavior. The stability analysis of the two equilibrium points shows that the equilibrium point free from math anxiety behavior is locally asymptotically stable. Additionally, this study also reveals that math anxiety behavior will disappear in less than 40 days through the basic reproduction number (Ro) obtained, which is 0.99 or less than 1.

Keywords: Amurang; mathematics anxiety; SIR model

Groundwater Study Using Vertical Electrical Sounding (VES) Data Based on Resistivity and Porosity of Rocks in Kampung Melayu, Bengkulu City

Fri, 12 Apr 2024 00:00:00 +0800

This research aims to identify groundwater based on the value of resistivity and porosity of rocks, which are important parameters in the management of groundwater resources and Development Planning in the region. This groundwater research using Vertical Electrical Sounding (VES) data based on the value of resistivity and porosity of rocks was carried out by measuring resistivity using the (VES) method at 20 sounding points located in Kampung Melayu District, Bengkulu City. The VES method is one of the approaches in the geoelectric method to determine the lithological characteristics of subsurface rocks. Resistivity Data obtained were then inverted and analyzed and interpreted to obtain lithology of subsurface rocks and groundwater level distribution in Kampung Melayu, Bengkulu City. The results showed the presence of groundwater based on low resistivity anomaly values with a range of values from 5 to 30 meters in the West and 10 to 50 meters in the East, with resistivity values ranging between 5 Ω.m up to 45 Ω.m. This research is expected to make a significant contribution to the management of groundwater resources in the District of Kampung Melayu, Bengkulu City and can be the basis for development planning in the area. In addition, it is hoped that the results of this research can be a reference for further research in the field of hydrogeology and groundwater modeling.

Keywords: Aquifer; geoelectricity; groundwater; porosity; resistivity

Antioxidant Activity of Virgin Coconut Oil Emulsion Drink with The Addition of Cinnamon (Cinnamomum burmanii)

Sat, 13 Apr 2024 00:00:00 +0800

ABSTRACT

The aims of this study were to analyse the antioxidant activity and to determine the maximum concentration of cinnamon extract that can improve sensory attributes of VCO emulsion drink. The research method used is a completely randomized design (CRD) with five concentrations of cinnamon extract, i.e., 0% (P1), 2% (P1), 4% (P2), 6% (P3), and 8% (P3). Each treatment was triplicated. The results showed that all treatments exhibited stable emulsion with 0% creaming index. VCO emulsion drink with cinnamon extract contained total phenol ranged from 19.88 mg GEA/100 g to 28.58 mg GEA/100 g, with increasing antioxidant activity, expressed as percentage of inhibition, where P1: 80.35%; P1: 85.59%; P2: 86.38%, P3: 87.43%, and P4: 88.54%, respectively. It was concluded that cinnamon extract could increase the antioxidant activity of VCO emulsion drinks. Increasing percentage of cinnamon extract can increase the total phenol content, hence increase the inhibitory power on the formation of peroxide compounds. The addition of 6% cinnamon is the maximum limit that can improve the panellists’ liking for the overall sensory attributes of the VCO emulsion drink.

Keywords: Antioxidant activity; cinnamon; VCO emulsion