Articles
<![CDATA[VIBRATION REDUCTION ON SINGLE-LINK FLEXIBLE MANIPULATOR USING H CONTROL ]]>
<![CDATA[Saragih, Roberd]]>;
<![CDATA[Tarwidi, Dede]]>
<![CDATA[ Journal of the Indonesian Mathematical Society Volume 14 Number 2 (October 2008) ]]>
Publisher : <![CDATA[IndoMS ]]>
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DOI: 10.22342/jims.14.2.52.73-82
<![CDATA[This paper is concerned with the vibration and position control of a single link flexible manipulator. Robot link manipulators are widely used in various industrial applications. It is desirable to build light weight flexible manipulators. Light flexible manipulators have a variety of applications, most significantly in space exploration,manufacturing automation, construction, mining, and hazardous operation. Timoshenko beam theory is used to derive mathematical model of a flexible manipulator. The dynamic equations of motion are obtained using the Lagrange's formulation of dynamics.The Hinfin; controller is designed for vibration and position control of the system. Simulations are presented and show that vibration and position control of a single flexible link can be controlled with the designed Hinfin; controller.DOI :Â http://dx.doi.org/10.22342/jims.14.2.52.73-82]]>
<![CDATA[Performance Evaluation of Various Phase Change Materials for Thermal Energy Storage of A Solar Cooker via Numerical Simulation ]]>
<![CDATA[Tarwidi, Dede]]>;
<![CDATA[Murdiansyah, Danang Triantoro]]>;
<![CDATA[Ginanjar, Narwan]]>
<![CDATA[ International Journal of Renewable Energy Development Vol 5, No 3 (2016): October 2016 ]]>
Publisher : <![CDATA[Center of Biomass & Renewable Energy, Diponegoro University ]]>
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DOI: 10.14710/ijred.5.3.199-210
<![CDATA[In this paper, thermal performance of various phase change materials (PCMs) used as thermal energy storage in a solar cooker has been investigated numerically. Heat conduction equations in cylindrical domain are used to model heat transfer of the PCMs. Mathematical model of phase change problem in the PCM storage encompasses heat conduction equations in solid and liquid region separated by moving solid-liquid interface. The phase change problem is solved by reformulating heat conduction equations with emergence of moving boundary into an enthalpy equation. Numerical solution of the enthalpy equation is obtained by implementing Godunov method and verified by analytical solution of one-dimensional case. Stability condition of the numerical scheme is also discussed. Thermal performance of various PCMs is evaluated via the stored energy and temperature history. The simulation results show that phase change material with the best thermal performance during the first 2.5 hours of energy extraction is shown by erythritol. Moreover, magnesium chloride hexahydrate can maintain temperature of the PCM storage in the range of 110-116.7°C for more than 4 hours while magnesium nitrate hexahydrate is effective only for one hour with the PCM storage temperature around 121-128°C. Among the PCMs that have been tested, it is only erythritol that can cook 10 kg of the loaded water until it reaches 100°C for about 3.5 hours.Article History: Received June 22nd 2016; Received in revised form August 26th 2016; Accepted Sept 1st 2016; Available onlineHow to Cite This Article: Tarwidi, D., Murdiansyah, D.T, Ginanja, N. (2016) Performance Evaluation of Various Phase Change Materials for Thermal Energy Storage of A Solar Cooker via Numerical Simulation. Int. Journal of Renewable Energy Development, 5(3), 199-210.http://dx.doi.org/10.14710/ijred.5.3.199-210]]>
<![CDATA[An enthalpy-based finite element method for solving two-phase Stefan problem ]]>
<![CDATA[Dede Tarwidi]]>
<![CDATA[ Indonesia Journal on Computing (Indo-JC) Vol. 4 No. 1 (2019): Maret, 2019 ]]>
Publisher : <![CDATA[School of Computing, Telkom University ]]>
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DOI: 10.21108/INDOJC.2019.4.1.252
<![CDATA[Stefan problem is a problem involving phase transition from solid to liquid or vice versa where boundary between solid and liquid regions moves as function of time. This paper presents numerical solution of one-dimensional two-phase Stefan problem by using finite element method. The governing equations involved in Stefan problem consist of heat conduction equation for solid and liquid regions, and also transition equation in interface position (moving boundary). The equations are difficult to solve by ordinary numerical method because of the presence of moving boundary. As consequence, the equations is reformulated into the form of internal energy (enthalpy). By the enthalpy formulation, solution of the heat conduction equations is no longer concerning the phase state of material. The advantage of the enthalpy formulation is that, finite element method can be easily implemented to solve Stefan problem. Numerical simulation of interface position, temperature profile, and temperature history has good agreement with the exact solution. The approximation of interface position using finite element method was found that it is more accurate than the approximation by using Godunov method. The simulation results also reveal that the finite element method for solving Stefan problem have smaller mean absolute error than the Godunov method.]]>
<![CDATA[Numerical Simulation of MEMS Technology Integrated in a Small-Caliber Projectile ]]>
<![CDATA[Dede Tarwidi]]>
<![CDATA[ International Journal on Information and Communication Technology (IJoICT) Vol. 2 No. 1 (2016): June 2016 ]]>
Publisher : <![CDATA[School of Computing, Telkom University ]]>
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DOI: 10.21108/IJOICT.2016.21.73
<![CDATA[In this paper, numerical simulation of small-caliber projectile during external ballistic is presented. This work is aimed to find safe location to install microelectromechanical system (MEMS) inside a small-caliber projectile based on history and distribution of temperature. The MEMS technology is applied to increase performance of the projectile and it must be protected from damage due to high temperature during internal and external ballistic. Heat conduction equation in cylindrical domain is used to describe transient temperature of smallcaliber projectile. Finite element method with the appropriate boundary conditions is adopted to solve the heat conduction equation and to obtain temperature distribution inside projectile. Numerical results show that heat transfer behavior of the projectile at any point is greatly affected by the value of thermal conductivity of material while the external convection does not significantly affect to the heat distribution. The maximum temperatures obtained from temperature history are below threshold value of MEMS damage that is 71℃. The MEMS technology can be installed anywhere inside the projectile except at the rear surface of the projectile which experienced friction with the inner surface of gun barrel during internal ballistics.]]>
<![CDATA[VIBRATION REDUCTION ON SINGLE-LINK FLEXIBLE MANIPULATOR USING H∞ CONTROL ]]>
<![CDATA[Roberd Saragih]]>;
<![CDATA[Dede Tarwidi]]>
<![CDATA[ Journal of the Indonesian Mathematical Society Volume 14 Number 2 (October 2008) ]]>
Publisher : <![CDATA[IndoMS ]]>
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DOI: 10.22342/jims.14.2.52.73-82
<![CDATA[This paper is concerned with the vibration and position control of a single link flexible manipulator. Robot link manipulators are widely used in various industrial applications. It is desirable to build light weight flexible manipulators. Light flexible manipulators have a variety of applications, most significantly in space exploration,manufacturing automation, construction, mining, and hazardous operation. Timoshenko beam theory is used to derive mathematical model of a flexible manipulator. The dynamic equations of motion are obtained using the Lagrange's formulation of dynamics.The H∞ controller is designed for vibration and position control of the system. Simulations are presented and show that vibration and position control of a single flexible link can be controlled with the designed H∞ controller.DOI : http://dx.doi.org/10.22342/jims.14.2.52.73-82]]>
<![CDATA[Tourism Recommender System Using Item-Based Hybrid Clustering Method (Case Study: Bandung Raya Region) ]]>
<![CDATA[Qisti R Arvianti]]>;
<![CDATA[Z. K. Abdurahman Baizal]]>;
<![CDATA[Dede Tarwidi]]>
<![CDATA[ Journal of Data Science and Its Applications Vol 2 No 2 (2019): Journal of Data Science and Its Applications ]]>
Publisher : <![CDATA[Telkom University ]]>
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DOI: 10.34818/jdsa.2019.2.35
<![CDATA[The recommender system can be used to provide recommender for an item based on the highest. Therefore, the information recommended by the system can be as needed. The recommender system can help tourists to determine their travel choices, especially for tourists in the city of Bandung. In the recommender system there are two commonly used methods, namely collaborative filtering and content-based filtering methods. However, both methods still have drawbacks among them, in content-based filtering methods cannot recommend various items. While the collaborative filtering method cannot recommend items that have not been rated at all or cold start problems. The collaborative filtering method also cannot recommend to new users because new users do not have history. With the shortcomings of the two methods, the item-based clustering hybrid method (ICHM) is proposed to combine the two methods. The analysis was carried out by comparing the Mean Absolute Error (MAE) on several tests that have been carried out. In a cluster of 30 and c coefficient of 0.9, the average MAE value obtained is 0.2459 in cold start problems and 0.2488 in non cold problems. The smaller the MAE value is generated, that means the higher the level of accuracy.]]>
<![CDATA[Penerapan Aplikasi Pembelajaran Berbasis Multimedia untuk Menunjang Proses Belajar Mengajar di SD Negeri Kertasari 01 Kabupaten Bandung ]]>
<![CDATA[Dede Tarwidi]]>;
<![CDATA[Putu Harry Gunawan]]>;
<![CDATA[Didit Adytia]]>
<![CDATA[ Charity : Jurnal Pengabdian Masyarakat Vol 3 No 2 (2020): Charity - Jurnal Pengabdian Masyarakat ]]>
Publisher : <![CDATA[PPM Universitas Telkom ]]>
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DOI: 10.25124/charity.v3i2.2357
<![CDATA[Makalah ini menyajikan penerapan aplikasi pembelajaran interaktif berbasis multimedia untuk menunjang proses pelajar pengajar di SD Negeri Kertasari 01 Kabupaten Bandung. Penerapan aplikasi pembelajaran ini dituangkan kedalam sebuah pelatihan pembuatan konten pembelajaran interaktif dengan multimedia. Masyarakat sasar yang dijadikan sebagai mitra adalah guru-guru SD Negeri Kertasari 01 Desa Tarumajaya Kecamatan Kertasari Kabupaten Bandung yang jaraknya sekitar 42 km dari Telkom University. Permasalahan yang dihadapi oleh masyarakat sasar adalah kurangnya media interaktif yang menunjang proses belajar mengajar, dalam satu kelas jumlah siswa terlalu banyak, proses penyampaian materi masih menggunakan papan tulis, siswa masih menggunakan buku ajar yang konvensional, keterbatasan waktu belajar siswa di sekolah. Untuk mengatasi permasalahan-permasalahan tersebut, salah satu solusinya adalah dengan pembuatan materi ajar interaktif berbasis teknologi multimedia. Hal inilah yang mendorong kami untuk memberikan pelatihan bagi para guru SD Negeri Kertasari 01 dalam pembuatan materi ajar dengan bantuan multimedia. Untuk mengukur apakah pelatihan ini memberikan pengaruh signifikan terhadap kemampuan peserta pelatihan dalam membuat materi ajar berbasis multimedia, kami melakukan observasi kemampuan peserta sebelum dan sesudah pelatihan. Hasil observasi kemudian dianalisis menggunakan t-test. Hasil dari analisis menunjukkan terdapat cukup bukti dengan tingkat kesalahan 5% bahwa ada perubahan yang signifikan dalam pelatihan pembuatan konten pembelajaran interaktif berbasis multimedia.]]>
<![CDATA[Simulasi Gelombang Laut Di Daerah Selatan Jawa Dengan Model Swan ]]>
<![CDATA[Muhammad Rafiuddin]]>;
<![CDATA[Didit Adytia]]>;
<![CDATA[Dede Tarwidi]]>
<![CDATA[ eProceedings of Engineering Vol 5, No 2 (2018): Agustus 2018 ]]>
Publisher : <![CDATA[eProceedings of Engineering ]]>
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<![CDATA[Abstrak Dalam perancangan struktur offshore platform, informasi saintifik gelombang yang akurat sangat dibutuhkan untuk menghindari kesalahan pengukuran yang bisa mengakibatkan defisiensi desain. Dalam tugas akhir ini, digunakan model gelombang phase-averaged SWAN (Simulating Waves Nearshore) untuk menyimulasikan gelombang signifikan dan gelombang swell daerah perairan di selatan pulau jawa. Simulasi gelombang dilakukan dengan menggunakan data input angin dari ECMWF (European Centre for MediumRange Weather Forecasts) dan data batimetri yang diperoleh dari GEBCO (General Bathymetric Chart of the Ocean). Hasil simulasi yang diperoleh akan dibandingkan dengan data buoy BPPT (Badan Pengkajian dan Penerapan Teknologi) dari tanggal 3 Mei 2014 hingga tanggal 30 September 2014. Perbandingan dengan data pengukuran dari BPPT menunjukkan bahwa hasil simulasi yang diperoleh sudah relatif akurat. Kata kunci : offshore platform, model SWAN, swell Abstract In order to design an offshore platform structure, accurate scientific information is highly needed to avoid measurement error that can leads to design deficency. In this paper, a phase-averaged wave model SWAN (Simulating Waves Nearshore) used to simulate the significant wave height and swell in southern part ofJava. Wind input data from ECMWF (European Centre for Medium-Range Weather Forecasts) and bathymetry from GEBCO (General Bathymetric Chart of the Ocean) used as input model to simulate the wind wave. Simulation results will then be compared with BPPT buoy data from 3 May 2014 to 30 September 2014. Comparison with measurement data from BPPT shows that obtained simulation result isrelatively accurate. Keywords: offshore platform, SWAN model, swell]]>
<![CDATA[Simulasi Pengaruh Intensitas Hujan Terhadap Ketinggian Banjir Menggunakan Metode Smoothed Particle Hydrodynamics (SPH) ]]>
<![CDATA[Emha Ainun]]>;
<![CDATA[Jondri Jondri]]>;
<![CDATA[Dede Tarwidi]]>
<![CDATA[ eProceedings of Engineering Vol 3, No 1 (2016): April, 2016 ]]>
Publisher : <![CDATA[eProceedings of Engineering ]]>
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<![CDATA[Berbagai fenomena alam seperti gunung berapi, banjir, tanah longsor, dan gempa bumi dapat dimodelkan dan disimulasikan dengan mengetahui parameter yang mempengaruhi fenomena tersebut. Salah satu fenomena yang cukup menarik untuk disimulasikan adalah banjir. Aliran fluida seperti banjir dapat dimodelkan menggunakan metode partikel. Metode partikel yang banyak digunakan dalam bidang dinamika fluida adalah Smoothed Particle Hydrodynamics (SPH). Dalam metode SPH, fluida direpresentasikan sebagai bagian diskrit yang disebut partikel. Setiap pertikel SPH memiliki sifat tersendiri seperti percepatan, kecepatan, densitas dan posisi. Gerak dari setiap partikel SPH dikendalikan oleh dua persamaan utama, yaitu persamaan Navier-Stokes (N-S) dan persamaan kontinuitas. Dalam tugas akhir ini, telah dibangun SPH simulator yang dimanfaatkan untuk simulasi banjir. Berdasarkan hasil simulasi yang telah dilakukan, menaikkan jumlah celah menjadi dua kali lipat mengakibatkan kenaikan ketinggian banjir meningkat lebih dari 50%. Kata kunci: Smoothed Particle Hydrodynamics, intensitas curah hujan, ketinggian banjir.]]>
<![CDATA[Simulasi Bioheat Transfer Untuk Perencanaan Cryosurgery Pada Kanker Paru-paru ]]>
<![CDATA[Citra Wahyu Fadmawati]]>;
<![CDATA[S.S. Prasetyawati S.S. Prasetyawati]]>;
<![CDATA[Dede Tarwidi]]>
<![CDATA[ eProceedings of Engineering Vol 2, No 3 (2015): Desember, 2015 ]]>
Publisher : <![CDATA[eProceedings of Engineering ]]>
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<![CDATA[Pada Tugas Akhir ini akan membahas simulasi pemusnahan sel kanker yang terjadi pada organ paru-paru menggunakan proses cryosurgery. Pemusnahan dilakukan dengan cara mengalirkan cairan nitrogen kemudian akan menyebarkan suhu yang sangat dingin. Distribusi suhu dilakukan dengan menggunakan pengembangan skema numerik Godunov dan metode volume hingga. Persamaan temperatur yang digunakan mengaplikasikan perubahan fase yang melibatkan batas bergerak. Persamaan numerik divalidasi dengan solusi eksak, sehingga memberikan hasil yang akurat dan dapat digunakan pada sistem dua dimensi. Pada analisa ini akan lebih detail pada pengembangan simulasi numerik satu dimensi dan dua dimensi untuk simulasi perpindahan panas. Hasil simulasi berupa gambar yang memberikan infomasi profil temperatur dan posisi interface, sehingga dapat terlihat jelas bagaimana proses cryosurgery dapat terjadi. Dengan simulasi ini diharapkan dapat menentukan waktu optimal dari proses cryosurgery itu sendiri, sehingga dapat mengetahui waktu yang dibutuhkan sedemikian hingga memaksimalkan jaringan kanker dan meminimalkan jaringan sehat disekitar akibat dari proses cryosurgery. Sehingga dengan melihat hasil simulasi, dokter dapat meminimalisasi resiko yang diakibatkan pada proses yang berjalan secara nyata. Kata Kunci : cryosurgery, perpindahan panas, metode godunov, metode volume hingga.]]>
