Judul: Development of Wet Muck Monitoring Information System at PT Freeport Indonesia’s Grasberg Block Cave Mine
Abstrak: Ore mining at PT. Freeport Indonesia (PTFI)’s Grasberg Block Cave (GBC) underground mine using the block caving system has potential wet muck hazard that can cause casualties, property loss and production disruption due to its ore position which is below the Grasberg open pit. The wet muck classification and slides occurrence as well as the result of their analysis need to be standardized and recorded to predict the occurrence of wet muck slide in the future. For this reason, it is necessary to build an information system as one of the hazard mitigation efforts. The objectives of this research are (1) to identify the profile / characteristics of wet muck monitoring, (2) to analyze the requirements and specifications of wet muck monitoring information system, and (3) to develop a prototype of wet muck monitoring information system. This research was conducted in 7 stages using the System Development Life Cycle (SDLC) methodology with prototyping approach. The first stage is to identify the profile / characteristics of wet muck monitoring through literature studies, in-depth interviews and discussions with technical experts involved in monitoring. The second stage is requirements and specifications analysis of the required monitoring system using fit & gap analysis and feasibility study methods. The third stage is system analysis using data flow diagram (DFD). The fourth stage is system design including database design using Entity Relationship Diagram (ERD), process design and user interface design. The fifth stage is development of system information prototype based on proposed system and new business process. The sixth stage is testing the prototype using black box testing method. The seventh stage is user interface usability and ease of use evaluation using System Usability Scale (SUS) method. The results showed that the wet muck monitoring information system requires four functions which include (1) data retrieval on the field, with mobile-based application as the solution, (2) data storage to a centralized database system, with MS SQL Server based geoscience application as the solution, (3) reporting and data analysis tools, with VBA MS Excel as the solution, and (4) spatial information visualization, with web-based Geographic Information System (GIS) as the solution. The prototype testing result showed that system functionality can run well as expected, meanwhile, the usability evaluation with final score 84.46 as the result shows that it has an excellent level of acceptance for respondens as users
Keyword: Geographic Information System (GIS), Mobile Application, Underground Mine, System Development Life Cycle, Prototyping

Judul: Pengembangan Sistem Informasi Manajemen Perawatan Aset Big Gossan Mill Facility Pt Freeport Indonesia
Abstrak: Kegiatan perawatan aset perusahaan sangat berpengaruh pada kegiatan operasional. Ketersediaan aset dan berjalan sesuai fungsinya menjadi hal yang penting bagi perusahaan. Teknologi perawatan aset telah mengalami perkembangan pada era Industri 4.0 sehingga perlu memilih teknologi yang tepat pada kegiatan perawatan aset. PT Freeport Indonesia telah memiliki perangkat pedukung kegiatan perawatan aset meliputi sistem kontrol, sistem basis data, pelaporan downtime dan sistem Enterprise Resource Planning (ERP). Manajemen perawatan aset yang kurang tepat menyebabkan terjadinya pembengkakan biaya dan kerugian akibat menurunnya pendapatan yang disebabkan terganggunya proses produksi, meningkatnya biaya perawatan untuk mempermudah dan meningkatkan sistem yang ada. Penelitian ini bertujuan untuk (1) Mengidentifikasi profil proses perawatan aset pada area Big Gossan Mill Facility (BGMF) PT Freeport Indonesia (PTFI),(2) Menganalisis kebutuhan dan spesifikasi sistem informaasi manajemen perawatan asset di area BGMF, dan (3) Mengembangkan prototipe sistem informasi perawatan aset pada area BGMF. Penelitian dilakukan menggunakan langkah-langkah dalam proses System Development Life Cycle (SDLC). Data diperoleh melalui studi literatur dan wawancara pada narasumber untuk mendapatkan informasi dalam rangka identifikasi profil alur pekerjaan perawatan aset dan juga analisis kebutuhan. Investigasi sistem dilakukan dengan menggunaan metode analisis fit & gap dan analisis kelayakan. Analisis sistem dilakukan dengan menggunakan data flow diagram (DFD), perancangan sistem informasi dengan merancang solusi dan usulan business process serta basis data. Pengembangan SI dilakukan dengan metode prototyping yang ditampilkan dalam bentuk layar antar muka. Pengujian fungsional sistem dilakukan dengan metode blackbox testing, focus group discussion (FGD), uji kelayakan dan kemudahan antarmuka menggunakan uji Sistem Usability Scale (SUS). Hasil penelitian menunjukan bahwa profil perawatan aset pada area BGMF yang meliputi analisis organisasi Ops.Maintenance,perilaku tindakan perawatan, beserta aset dan juga sistem informasi yang tersedia, dibutuhkan sistem informasi perawatan aset yang memiliki fungsi-fungsi untuk (1) Pencatatan dan pengolahan data aset secara otomatis terhadap enam jenis informasi, (2) input data manual dari pihak Ops. Maintenance, (3) notifikasi untuk event atau kejadian tertentu, (4) Visualiasi terhadap data/informasi berbasis web. Menurut pengujian metode blackbox testing semua fungsi berjalan baik dan hasil evaluasi kelayakan dan kemudahan menunjukan nilai SUS 78.5 yang menunjukan penerimaan yang baik (acceptable) dari responden, dengan adjective rating antara good dan excellence.
Keyword: Operational Asset, Preventive Maintenance, Prototype, System Development Life Cycle and Web Application

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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