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Your search keyword '"Firdaus, Kemal"' showing total 8 results
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8 results on '"Firdaus, Kemal"'

1. Non-Hydrostatic Model for Simulating Moving Bottom-Generated Waves: A Shallow Water Extension with Quadratic Vertical Pressure Profile

Author

Firdaus, Kemal and Behrens, Jörn

Subjects
Mathematics - Numerical Analysis, Computer Science - Computational Engineering, Finance, and Science
Abstract

We formulate a depth-averaged non-hydrostatic model to solve wave equations with generation by a moving bottom. This model is built upon the shallow water equations, which are widely used in tsunami wave modelling. An extension leads to two additional unknowns to be solved: vertical momentum and non-hydrostatic pressure. We show that a linear vertical velocity assumption turns out to give us a quadratic pressure relation, which is equivalent to Boussinesq-type equations. However, this extension involves a time derivative of an unknown parameter, rendering the solution by a projection method ambiguous. In this study, we derive an alternative form of the elliptic system of equations to avoid such ambiguity. The new set of equations satisfies the desired solubility property, while also consistently representing the non-flat moving topography wave generation. Validations are performed using several test cases based on previous experiments and a high-fidelity simulation. First, we show the efficiency of our model in solving a vertical movement, which represents an undersea earthquake-generated tsunami. Following that, we demonstrate the accuracy of the model for landslide-generated waves. Finally, we compare the performance of our novel set of equations with the linear and simplified quadratic pressure profiles.

Published
2024

5. Model of orangutan population dynamics by considering infanticide and Minimum Viable Population factors.

Author

Mubarok, Nahrul, Jabriel, Karsten Maynard, Firdaus, Kemal, and Suandi, Dani

Subjects
ORANGUTANS, POPULATION dynamics, INFANTICIDE, NONLINEAR differential equations, NONLINEAR equations, LIFE cycles (Biology), RARE animals
Abstract

Orangutans are rare animals whose populations are threatened with extinction. Several factors that influence the extinction of orangutans are influenced by humans, such as deforestation and hunting activities. Herein we will focus on studying the factors of extinction caused without human intervention. These factors include the slow life cycle due to the long interbirth interval of orangutans and the presence of infanticide. To examine the behavior, a model of a three-dimensional non-linear system of differential equations is constructed to modeled orangutan population. The model is constructed based on the age structure due to different levels of productivity. This model also considers the Minimum Viable Population (MVP) and infanticide cases which are represented by the functional response of Holling type II and Allee effect, respectively. In this study, the existence and stability of the equilibrium point are investigated analytically for cases without infanticide. Meanwhile, the general case is analyzed numerically. Numerical simulations are also carried out to examine the existence of the bifurcation and at the same time to confirm the analytical results. From this model, we get three equilibrium points where two interior equilibria and one trivial equilibrium. Our analysis shows that the trivial equilibrium is always unconditionally stable. This means that if the orangutan population is close to extinction, then the orangutan population will be headed for extinction. The boundary of the extinction area is also obtained to maintain the coexistence of the orangutan population by paying attention to the proportion of orangutans that must always be above that boundary. In addition, numerical results confirm that the greater the infanticide factor, the wider the area of population extinction, which has an impact on the smaller proportion of the orangutan population. The results of this study suggest to policy makers to always keep the population proportion above the boundary that we find so that extinction can be avoided. [ABSTRACT FROM AUTHOR]

Published
2024
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7. TA : Rancang Bangun Sistem Informasi Pelayanan dan Informasi Kesehatan di Pusat Kesehatan Masyarakat Menggunakan SMS Gateway

Author

Akbar, Adam Wiradyta Firdaus Kemal and Akbar, Adam Wiradyta Firdaus Kemal

Abstract

Puskesmas Rejowinangun merupakan salah satu Puskesmas yang berada di wilayah Kecamatan Kota Trenggalek, Kabupaten Trenggalek. Saat ini Puskesmas Rejowinangun masih menggunakan pencatatan manual dalam pelayanan kesehatan. Puskesmas ini mengandalkan ingatan seorang tenaga kesehatan untuk mencari catatan status pasien dalam rak family folder. Puskesmas belum memiliki sistem antrian dan pencatatan pembayaran yang baik, sehingga jumlah penanganan medis dengan income sering tidak balance. Puskesmas perlu memiliki sebuah perangkat lunak berbentuk sistem informasi yang dapat membantu proses pelayanan kesehatan. Cakupan pelayanan kesehatan ini antara lain Unit Balai Pengobatan (BP), Unit Kesehatan Ibu dan Anak (KIA), Unit Gigi, Unit Gawat Darurat (UGD), Unit Manajemen Terpadu Balita Sakit (MTBS), Unit Laboratorium dan Unit Resep. Data pasien diolah untuk mengetahui sebaran kasus penyakit, wabah penyakti menular dan Kejadian Luar Biasa (KLB). Data tersebut juga dipakai sebagai acuan perencaan penanganan isu kesehatan melalui upaya penyampaian informasi kesehatan. Dengan memanfaatkan sistem informasi pelayanan dan informasi kesehatan, Puskesmas Rejowinangun diharapkan dapat mengintegrasikan pelayanan masing-masing unit sehingga proses kerja berjalan lebih efektif serta menghasilkan laporan yang bisa dipakai acuan melakukan upaya penyampaian informasi seputar kesehatan kepada masyarakat.

Published
2014

8. Numerical Study for Unsteady Waves Generated by Flow over a Permeable Wavy Bed.

Author

Magdalena, Ikha and Firdaus, Kemal

Subjects
FLUID dynamics, WAVES (Fluid mechanics), BREAKWATERS, DARCY'S law, POTENTIAL theory (Mathematics), BOUSSINESQ equations, FINITE differences
Abstract

In this paper, we formulate a numerical model to study unsteady waves generated by fluid flow over a permeable wavy bed. The model is derived from boundary value problems using potential theory. We solve the model numerically using a finite difference method. As a result, we found that the flow over a porous layer generates wave disturbed by bumps on the porous layer. The simulation also showed that the wave profile shifts from the permeable bed. The results of this study can be incorporated into the design of submerged artificial and natural breakwaters. [ABSTRACT FROM AUTHOR]

Published
2022
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