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: Information System Development for Monitoring Ore Content in PT Freeport Indonesia
Abstrak: Proses pengolahan bijih (ore) di PT Freeport Indonesia menghasilkan stream feed, tailing dan concentrate, Pemantauan kandungan bijih di setiap stream saat ini dilakukan dengan cara pengambilan sampel setiap empat jam untuk dilakukan analisis kandungan logam di laboratorium. Gap waktu selama empat jam ini membuat waktu koreksi proses di pabrik menjadi terlalu lama. Efeknya, target produksi konsentrat (grade tembaga) seringkali tidak tercapai. Solusi bagi adanya gap waktu adalah dengan mengimplementasikan sebuah sistem pemantauan kandungan logam dalam proses pengolahan secara real-time. Hasil yang akan terjadi adalah perubahan pola kerja pada proses evaluasi dan proses koreksi/reaksi dari yang sebelumnya kurang lebih empat jam menjadi setiap menit. Penelitian ini bertujuan untuk mengidentifikasi proses pengolahan bijih (ore) yang membutuhkan data analisis online analyzer beserta fitur data online analyzer dan merancang prototipe penampilan data online analyzer. Penelitian dilakukan dengan pengembangan visualisasi serta proses perancangan prototipe sistem online analyzer. System requirement bagi pengembangan visualisasi dilakukan dengan metode in-depth interview dengan berbagai stakeholder yang berasal dari departemen Metalurgi, departemen Mill Operation, departemen Assay & Analytical Laboratory dan manajemen divisi Concentrating. Pengembangan prototipe visualisasi sistem PI memiliki fitur data seperti alarm, grafik dan tabel yang berguna untuk memantau proses dan target pengolahan. Alarm disajikan pada antarmuka sebagai sistem pencegahan jika terdapat kerusakan atau permasalahan pada online analyzer, sehingga dapat memangkas proses perbaikan. Hasil user acceptance test pada 4 aspek (penampilan data real-time, fitur alarm, legend/keterangan, pengaturan waktu) menunjukkan keberterimaan pada expected result. Implementasi sistem visualisasi online analyzer dibutuhkan pihak ketiga yaitu OSIsoft sebagai verifikator. Sistem visualisasi online analyzer digunakan sebagai feeder data otomatis bagi sistem kontrol Ball-Mill dan Flotation Column.
Keyword: Online Analyzer, Prototype, PTFI, Data Visualization

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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