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Comparative Modeling of Pineapple Production Using Gaussian GLM and Random Forest Regression Radot MH Siahaan; Indah Gumala Andirasdini; Fuji Lestari; Dwi Mahrani; Amalia Listiani
ZERO: Jurnal Sains, Matematika dan Terapan Vol 10, No 1 (2026): Zero: Jurnal Sains Matematika dan Terapan
Publisher : UIN Sumatera Utara

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30829/zero.v10i1.28721

Abstract

This study aims to conduct a comparative modelling of pineapple production at PT Great Giant Pineapple (GGP) using Gaussian GLM as parametric statistical approach and Random Forest Regression method as machine learning based on monthly data from 2014 to 2022. Multicollinearity testing and distribution fitting were conducted to validate the Gaussian assumption. For the Random Forest Regression, hyperparameters were optimized by tuning the number of trees (ntree) and the number of predictors at each split (mtry) with model stability evaluated using Out-of-Bag (OOB) error. The Gaussian GLM achieved a MAPE of 8.41% (R² = 0.106) for the GP3 clone and 11.27% (R² = 0.149) for the F180 clone. Random Forest Regression produced a testing MAPE of 9.28% (R² = 0.144) for GP3 and 12.11% (R² = 0.105) for F180. While both models achieved low prediction error based on MAPE, they differed in identifying influential variables and showed limited explanatory power as indicated by low R² values. The Gaussian GLM identifies air pressure as significant for both clones and rainfall for F180 clone, while Random Forest consistently identifies rainfall as the most influential predictor. These findings confirm the complementary strengths of parametric and machine learning approaches in supporting climate-based production planning and risk mitigation.
Density Functional Theory (DFT) Study on Molecular Interaction between H2O and Graphene Daffa Hadyan Akmal; Amrina Mustaqim; Indah Gumala Andirasdini; Septia Eka Marsha Putra
Jurnal IPTEK Vol 30, No 1 (2026): May
Publisher : LPPM Institut Teknologi Adhi Tama Surabaya (ITATS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31284/j.iptek.2026.v30i1.8094

Abstract

Graphene has attracted significant attention as an anode material due to its high surface area and unique electronic properties. This study explores the adsorption behavior of H₂O molecules on graphene using Density Functional Theory (DFT) with the van der Waals density functional (vdW-DF). Various molecular orientations (zero-leg, one-leg, and two-leg) and adsorption sites (top, bridge, hollow) were analyzed. The results show that the most stable configuration is the two-leg orientation at the hollow site, with an adsorption energy of -0.123 eV. The findings suggest that the stability of the adsorbed system is governed more by the interaction between hydrogen atoms and the carbon surface than by the oxygen atom. All stable structures are characterized by adsorption distances between 2.8 and 3.2 A. The interaction is classified as physisorption due to its low energy and minimal charge transfer. These results are consistent with previous studies, confirming the key role of molecular orientation and adsorption site in determining the adsorption behavior of H₂O on graphene.
Peningkatan Literasi dan Kompetensi IoT Siswa SMK Dharmapala Panjang Listra Yehezkiel Ginting; Ahmad Suaif; Amrina Mustaqim; Nike Dwi Grevika Drantantiyas; Septia Eka Marsha Putra; Christio Revano Mege; Indah Gumala Andirasdini
JPEMAS: Jurnal Pengabdian Kepada Masyarakat Vol. 4 No. 2 (2026): JPEMAS: Jurnal Pengabdian Kepada Masyarakat
Publisher : Yayasan Pendidikan Tanggui Baimbaian

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.71456/adc.v4i2.1758

Abstract

Kegiatan pengabdian kepada masyarakat ini dilatarbelakangi oleh masih terbatasnya pemahaman dan keterampilan siswa SMK dalam menguasai teknologi Internet of Things (IoT) serta belum optimalnya pembelajaran berbasis praktik yang sesuai dengan kebutuhan industri di era digital. Tujuan kegiatan ini adalah untuk meningkatkan literasi teknologi, pemahaman konsep, dan keterampilan praktis siswa melalui pelatihan dan penerapan IoT berbasis pendekatan STEM (Science, Technology, Engineering, and Mathematics). Metode yang digunakan meliputi ceramah, diskusi interaktif, praktik langsung perakitan sistem IoT sederhana, serta evaluasi melalui pretest dan posttest terhadap 88 siswa jurusan kelistrikan SMK Dharmapala Panjang. Hasil kegiatan menunjukkan peningkatan signifikan pada seluruh indikator pemahaman, yaitu pemahaman implementasi IoT meningkat dari 43 menjadi 88 peserta (51,14%), komponen sistem IoT dari 55 menjadi 85 peserta (34,09%), jaringan komunikasi IoT dari 23 menjadi 84 peserta (69,32%), serta langkah pembuatan proyek IoT dari 22 menjadi 88 peserta (75,00%). Selain itu, peserta mampu merakit dan mengoperasikan sistem pengendalian lampu berbasis IoT menggunakan mikrokontroler secara mandiri. Hasil ini menunjukkan bahwa pendekatan pelatihan yang mengintegrasikan teori dan praktik secara langsung efektif dalam meningkatkan kompetensi teknis dan literasi digital siswa, sehingga kegiatan ini berkontribusi dalam mendukung penguatan pendidikan vokasi yang adaptif terhadap perkembangan teknologi dan kebutuhan dunia kerja.
Density Functional Theory (DFT) and Quasi Harmonic Approximation (QHA) on Isotope effect of Methane Absorbed on Ag(111) Surface Septia Eka Marsha Putra; Indah Gumala Andirasdini
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 14, No 1 (2024): April
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v14i1.71754

Abstract

We investigated the isotope effect of methane (CH4) on Ag(111) using van der Waals density functional and the quasi-harmonic approximation.In this study, we combined two methods to investigate the nuclear quantum effect in methane adsorption on an Ag(111) surface. We obtained that the adsorption potential energies of CD4on fcc Ag(111) surfaces are shallower than those of CH4, whereas the equilibrium distances from the surface are larger.The similiar finding also observed in our previous study, however, Ag(111) gives smaller energies.It is found that the similar softening of the C-H bond pointing toward the surface is the cause of the isotope effect. This softening leading to lowering the vibrational frequency and large zero-point energy difference between CH4and CD4.