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All Journal Bulletin of Scientific Contribution : Geology Indonesian Journal of Applied Sciences IJOG : Indonesian Journal on Geoscience Forum Geografi Sinkron : Jurnal dan Penelitian Teknik Informatika JITK (Jurnal Ilmu Pengetahuan dan Komputer) Buletin Sumber Daya Geologi Jurnal Teknologi Energi JATI (Jurnal Mahasiswa Teknik Informatika) REMIK : Riset dan E-Jurnal Manajemen Informatika Komputer Jurnal Infortech Indonesian Journal on Geoscience Jurnal Teknik Informatika (JUTIF) Indonesian Journal on Geoscience Journal of Geosciences and Applied Geology Jurnal Vokasi Bisnis Digital, Akuntansi Lembaga Keuangan Syariah dan Usaha Perjalanan Wisata
Adjat Sudradjat
Universitas Padjadjaran
Civil Engineering, Building, Construction & Architecture Computer Science & IT Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Energy Engineering Environmental Science Library & Information Science Other

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KRITERIA KERUSAKAN AKIBAT PELEDAKAN PADA PEMBUATAN TEROWONGAN CIURUG, TAMBANG EMAS PONGKOR, KABUPATEN BOGOR, PROVINSI JAWA BARAT Suwandhi, Awang; Rosana, Mega Fatimah; Sudradjat, Adjat; Wattimena, Ridho Kresna
Buletin Sumber Daya Geologi Vol 12 No 2 (2017): Buletin Sumber Daya Geologi
Publisher : Pusat Sumber Daya Mineral Batubara dan Panas Bumi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.47599/bsdg.v12i2.36

Abstract

Untuk mencapai urat (vein) bijih di lokasi Central pada Level 500 mdpl, Ciurug, dibuat terowongan baru yang dinamakan RU4C-L500 dengan menerapkan teknik peledakan. Terowongan tersebut dirancang berukuran lebar 4 m, tinggi 4 m dan panjang 100 m sampai ke cross-cut menuju urat bijih. Penelitian dilakukan dengan tujuan untuk mendapatkan kriteria kerusakan terowongan yang diakibatkan oleh induksi getaran peledakan yang berpotensi menghasilkan overbreak, sehingga ukuran terowongan menjadi lebih lebar dari rencana semula. Pendekatan Blast Damage Index (BDI) digunakan sebagai metode untuk memperoleh tingkat kerusakan terowongan tersebut. Terowongan menerobos batuan andesit vulkanik yang berdasarkan hasil pengujian memiliki kecepatan rambat gelombang seismik 4157 m/det, densitas 2,37 g/cc dan kuat tarik 8,10 MPa. Batuan tersebut tergolong batuan berkekuatan sedang hingga keras dengan nilai Rock Mass Rating (RMR) antara 58,3 sampai 69,5. Data getaran peledakan diukur dengan menggunakan geofon pada jarak yang aman dari titik ledakan dan menghasilkan Peak Vector Sum (PVS) berkisar antara 2 mm/s sampai 120 mm/s. Hasil pengolahan data getaran menunjukkan, bahwa nilai BDI sebesar 2 yang mengidentifikasi adanya ambrukan terowongan karena induksi getaran peledakan terjadi pada jarak kurang dari 3 m dari titik ledakan. Besar getaran peledakan yang mengambrukan batuan andesit vulkanik tersebut mencapai PVS 1170 mm/s. Pada jarak antara 3,0 m sampai 10 m tidak terjadi kerusakan terowongan yang parah dan dapat direhabilitasi. Kondisi tersebut diidentifikasi oleh nilai BDI 0,5 sampai 1. Kemudian pada jarak di atas 10 m induksi getaran peledakan tidak lagi berpengaruh terhadap kerusakan atau kestabilan dinding terowongan. 
THE RIGHT STEPS TOWARDS GRADUATION: NB-PSO SMART COMBINATION FOR STUDENT GRADUATION PREDICTION Kahfi, Ahmad Hafidzul; Prihatin, Titin; Yudhistira, Yudhistira; Sudradjat, Adjat; Wijaya, Ganda
Jurnal Teknik Informatika (Jutif) Vol. 5 No. 2 (2024): JUTIF Volume 5, Number 2, April 2024
Publisher : Informatika, Universitas Jenderal Soedirman

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52436/1.jutif.2024.5.2.1889

Abstract

The current digital era demands a more innovative approach in predicting student campuses considering that campuses are not only important for students but also for lecturers, student guardians and higher education institutions. Previous studies have used various machine learning methods such as Decision Trees, Neural Networks, Support Vector Machines, etc. in these predictions. The problem that occurs is that even though various machine learning methods have been used, there are still limitations in the accuracy and efficiency of predicting student admissions, The problem in question can be given a real example of a case that occurred. So with this problem the aim is to develop a more effective methodology in predicting student permits, with recommendations from an intelligent combination of two computational techniques Naive Bayes (NB) and Particle Swarm Optimization (PSO). This research methodology includes data collection, NB model development and model partnership with PSO. Student graduation data is used in model testing with evaluation based on metrics such as accuracy and Area Under the Curve (AUC). The results showed a significant increase in accuracy to 86.94% from 83.30% and AUC value from 0.860 to 0.884 when using the combination of NB and PSO compared to NB without either. The integration of NB and PSO has been proven to increase effectiveness in classifying student graduation prediction cases. This research opens up opportunities for the practical application of technology in the education sector and emphasizes the importance of using effective optimization and feature selection techniques in improving prediction results.
Ichnofossil of Nanggulan Deltaic System: Case Study of Watupuru Cross Section in Kulon Progo, Central Java, Indonesia Nuraini , Siti; Syafri, Ildrem; Muljana, Budi; Sudradjat, Adjat
Indonesian Journal on Geoscience Vol. 11 No. 2 (2024)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.11.2.295-312

Abstract

The Nanggulan Formation in Kulon Progo, Yogyakarta, Indonesia, is rich in ichnofossils as observed in a cross-section of the Watupuru River. This research aims to explore the relationship between ichnogenera, their behaviours and patterns during the deposition of the Nanggulan Formation in the Middle to Upper Eocene period. The study involved analyzing measured sections along the Watupuru River, paleocurrent measurements, and palynology. Seventeen ichnogenera were identified and linked to seven depositional facies within the Nanggulan Formation, i.e. Nummulites bank, prodelta, strand plain, delta front, delta plain, sandflat, and fluvial sand, categorized into autochthonous and allochthonous rock units. Allochthonous rocks, like tempestite and turbidite, were discovered within the autochthonous Nanggulan Formation with ichnogenera present in both types of rocks. Ichnofossils associated with the prodelta facies in autochthonous rocks included into Bergaueria, Siphonichnus, Phycodes, Trypanites, Treptichnus, Teredolites, Chondrites, and Thalassinoides, tend to indicate a muddy suspension environment. In contrast, the delta plain facies (FDP) indicating a calm oxidizing environment with ichnogenera contents like Teredolithes, Bergaueria, Scoyenia, Aulichnitus, Helminthopsis, Chondrites, Gastrochaelites, Ophiomorpha, and Siphonichnus were recognized. Factors influencing ichnofossil diversity include lighting, behaviour or adaptation to the environment, sedimentation rate, current control, and burrow infilling. The diversity of ichnofossils in allochthonous tempestite layers was influenced by post-catastrophic storm events. Barren ichnogenera at the base of tempestite layers indicated early storm surges, while the upper layers contained diverse ichnogenera such as Gastrochaelites, Psilonichnus, Bergaueria, and Planolites in the delta front facies (FDF). Tempestite layers in the sandflat facies (FSF) containing ichnogenera such as Thalassinoides, Bergaueria, Rhizocoralleum, Planolites, Cylindrichnus, and Siphonichnus, tend to show a favorable environment for organism post-storm.
Co-Authors Abdurrokhim ⠀ Adhitiawarman, Adhitiawarman Adi Supriyatna Aditia, Nita Ahmad Helman Hamdani, Ahmad Helman Awang Suwandhi Baginda Oloan Lubis Banu Dwi Hanggoro, Dimas Bernadeta Subandini Astuti Budi Muljana Dewi Laraswati Dicky Muslim Djajang Sukarna Dony Oscar dwi hartanto E. T. Paripurno Emi Sukiyah Febri Hirnawan Febrianti, Clara Ganda Wijaya, Ganda Ghofar Taufiq HARIYANTO HARIYANTO Hartono, Hill G. Hendri Hendri Henny Destiana Hill Gendoet Hartono Ildrem Syafri Irmawati Carolina Ishak Komarudin Ispandi Ispandi, Ispandi Kahfi, Ahmad Hafidzul kurnio, Hananto Mega Fatimah Rosana Mega Fatimah Rosana Mochammad Imron Awalludin Muhamadsyah, Faisal Muhammad Qomaruddin Nuraini , Siti Okki Verdiansyah Rachman Komarudin Rahdian Kusuma Atmaja Rahmat Tri Yunandar Retno Sari Ridho Kresna Wattimena Ridho Kresna Wattimena, Ridho Kresna Rino Ramadan Riyandi, Albert robi sopandi Rokhayati, Erna Rosana, Mega Fatimah Setianingsih Setianingsih, Setianingsih Setyo, Joko Sulis Suwandhi, Awang Suwandhi, Awang Syaiful Bachri Tutut Sunarminto Vijaya Isnaniawardhani Wina Widiati Yudhicara, Yudhicara Yudhistira Yudhistira