Articles
<![CDATA[Kontrol Optimum pada Model Prey-Predator dengan Pemanenan pada Ikan Prey dan Ikan Predator ]]>
<![CDATA[Oryza Safitri]]>;
<![CDATA[Mardlijah Mardlijah]]>
<![CDATA[ Limits: Journal of Mathematics and Its Applications Vol 16, No 1 (2019) ]]>
Publisher : <![CDATA[Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/limits.v16i1.4607
<![CDATA[Model prey-predator didasari oleh hubungan interaksi predasi antara suatu organisme yang memakan suatu organisme lainnya, dalam kasus ini yaitu ikan prey dan ikan predator. Selanjutnya diberi perlakuan pemanenan pada ikan prey dan ikan predator. Untuk menjaga agar tindakan pemanenan tidak mengakibatkan kelangkaan suatu jenis ikan, dilakukan kontrol optimum berupa penambahan makanan lain pada ikan predator. Kontrol optimum ini dimaksudkan agar hasil pemanenan yang didapatkan maksimal sekaligus menjaga keberlangsungan ekosistem pada ikan prey dan ikan predator. Kemudian didapatkan titik-titik ekuilibrium dengan satu titik ekuilibrium yang stabil yaitu di titik (75.39 , 4.20). Selanjutnya hasil kontrol optimal, populasi ikan prey dan ikan predator lebih banyak, dibandingkan populasi ikan prey dan ikan predator sebelum dikontrol.]]>
<![CDATA[Comparison between Fuzzy Logic Controller (FLC) and Fractional Order Proportional Integral Derivative (FOPID) Controller on Water Level and Steam Temperature of Steam Drum Boiler ]]>
<![CDATA[Zainullah Zuhri]]>;
<![CDATA[Mardlijah Mardlijah]]>;
<![CDATA[Didik Khusnul Arif]]>
<![CDATA[ (IJCSAM) International Journal of Computing Science and Applied Mathematics Vol 4, No 2 (2018) ]]>
Publisher : <![CDATA[Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j24775401.v4i2.3492
<![CDATA[Steam drum boiler is an important component of boiler on electric steam power plant which is useful to obtain steam. The obtained steam makes turbine spin. In order to obtain maximal result for the steam power plant (PLTU) 1-2 PT PJB UP Gresik, the water level of steam drum boiler must be 0.7625 m and the temperature of steam drum boiler must be 786 K. Thus, it needs some controller to keep the position of water level and the temperature stable. In this problem, we compare two controllers FLC and FOPID. It can be concluded that FLC works better than FOPID controller. Nevertheless, FOPID controller has faster response time than FLC, i.e. no overshoot and more robust when disturbance is present on the system.]]>
<![CDATA[Analysis Mathematical Model of Radicalization S(Susceptible) E(Extremists) R(Recruiters) I(Immunity) with Optimal Control ]]>
<![CDATA[Dauliyatu Achsina]]>;
<![CDATA[Mardlijah Mardlijah]]>
<![CDATA[ (IJCSAM) International Journal of Computing Science and Applied Mathematics Vol 7, No 2 (2021) ]]>
Publisher : <![CDATA[Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j24775401.v7i2.4605
<![CDATA[Radicalization is a process when people come to adopt increasingly extreme political or religious ideologies, radicalization almost occurs in almost all countries in the world. Seeing a number of cases in recent times, radicalization has become a major concern for the world, especially in the field of national security. Radicalization has become one of the focuses in the national security sector because it leads to acts of extremism, violence and terrorism. The level of radicalization is high in each year and continues to increase so special supervision is needed to control it because it causes huge financial losses. Therefore a preventive effort is needed to overcome this. Efforts to prevent radical movements have been widely used, ranging from direct or indirect, in addition some things have also been done directly by the government. So far it has not been seen how effective these efforts are. Radicalization is formed because of the influence of extremists and the recruiters group. Many individuals are affected and enter the group because they are influenced by the people in the group who are within their scope. To overcome these problems, a control is needed as an effort to prevent radicalism. Prevention efforts are in the form of strict sanctions given to recruiters. Next to find out how the influence of controls on individual groups of recruiters is needed a tool to represent the tool is a model. The mathematical model that is suitable for representing the appropriate problems of radicalization is the Susceptible (S) , Extremists (E) Recruiters (R), Immunity (I) model.]]>
<![CDATA[Optimal Feeding Strategy on Microalgae Growth in Fed-Batch Bioreactor Model ]]>
<![CDATA[Nailul Izzati]]>;
<![CDATA[Mardlijah Mardlijah]]>
<![CDATA[ (IJCSAM) International Journal of Computing Science and Applied Mathematics Vol 1, No 1 (2015) ]]>
Publisher : <![CDATA[Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j24775401.v1i1.1451
<![CDATA[Some countries in the world turn to alternative energy source to fulfill their necessity of fuel. One of the alternative fuels is biodiesel. Raw material of biodiesel can be produced by microalgae cultivation in fed-batch bioreactor. To improve the productivity of microalgae cultivation, we need to determine the optimal control of microalgae growth. This paper discusses mathematical model of microalgae growth in fed-batch bioreactor, and solves the optimal feeding strategy problem by using Pontryagin Minimum Principle. Then we compare the controlled microalgae growth model with the uncontrolled one. Numerical simulation with DOTcvpSB shows that the controlled microalgae growth model yields more harvest and less cost function than the uncontrolled one.]]>
<![CDATA[The Effect of Collector in Solar Still for Water Productivity Using Runge-Kutta Method ]]>
<![CDATA[Mardlijah Mardlijah]]>;
<![CDATA[Achmad Fatoni]]>;
<![CDATA[Lukman Hanafi]]>
<![CDATA[ (IJCSAM) International Journal of Computing Science and Applied Mathematics Vol 1, No 1 (2015) ]]>
Publisher : <![CDATA[Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j24775401.v1i1.1473
<![CDATA[Solar still is a renewable energy technology. It can reduce crisis of clean and healthy water in some countries. Solar still produces clean and healthy water using the sunlight, but the result of distillate water is not so much. Hence the need for modifications with the addition of collector can increase the yield of distillate water. Mathematical model of solar still with collector is in the form of system of differential equations. It can be solved numerically using Runge-Kutta method. From the simulation, we conclude that the collector increases the amount of distillate water in the solar still.]]>
<![CDATA[Desain Kontrol pada Model Gerak Lateral-Direksional Unmanned Aerial Vehicle (UAV) Menggunakan Output Feedback Control ]]>
<![CDATA[Wiwit Ratnasari]]>;
<![CDATA[Erna Apriliani]]>;
<![CDATA[Mardlijah Mardlijah]]>
<![CDATA[ Jurnal Sains dan Seni ITS Vol 11, No 2 (2022) ]]>
Publisher : <![CDATA[Lembaga Penelitian dan Pengabdian Kepada Masyarakat (LPPM), ITS ]]>
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DOI: 10.12962/j23373520.v11i2.75502
<![CDATA[Pengembangan teknologi di berbagai bidang dari tahun ke tahun semakin pesat, begitu pula pengembangan teknologi di bidang kedirgantaraan. Salah satu pengembangannya adalah pesawat tanpa awak atau Unmanned Aerial Vehicle (UAV). Dalam penelitian ini, dilakukan analisis sistem dan desain kontrol pada model gerak lateral-direksional UAV menggunakan Output Feedback Control. Sistem bersifat tidak stabil, terkontrol, dan teramati. Agar UAV menjadi stabil, maka dilakukan penerapan Pole Placement pada desain kontrol dengan 5 skenario feedback gain (K_1,K_2,K_3,K_4,K_5,) untuk memindahkan nilai eigen yang menyebabkan sistem UAV tidak stabil. Skenario pada sudut selip (β) paling baik adalah desain kontrol dengan K_4 yang waktu stabilnya paling cepat yaitu 322 s, begitu pula pada sudut roll (ϕ) skenario terbaik adalah desain kontrol dengan K_4 dimana pada waktu 172 s sudah stabil.]]>
<![CDATA[Kontrol Optimal Penyebaran COVID-19 Model SEIR di Jakarta ]]>
<![CDATA[Nada Fitriani Azzahra]]>;
<![CDATA[Hariyanto Hariyanto]]>;
<![CDATA[Mardlijah Mardlijah]]>
<![CDATA[ Jurnal Sains dan Seni ITS Vol 11, No 2 (2022) ]]>
Publisher : <![CDATA[Lembaga Penelitian dan Pengabdian Kepada Masyarakat (LPPM), ITS ]]>
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DOI: 10.12962/j23373520.v11i2.76998
<![CDATA[Penyakit coronavirus (COVID-19) masuk ke Indonesia dan pertama kali terdeteksi di Jakarta. Hingga Juli 2020, kasus positif COVID-19 di Jakarta menjadi penyumbang kasus positif terbanyak di Indonesia. Hal ini menunjukkan bahwa penyebaran COVID-19 semakin meningkat dan perlu penanganan yang lebih maksimal. Oleh karena itu, dalam penelitian ini dibahas tentang pemberian kontrol yang optimal untuk mengendalikan penyebaran COVID-19 di Jakarta dengan model SEIR (Susceptible Exposed Infected Recovered). Model SEIR yang digunakan merupakan hasil pengembangan dari model yang sudah ada dengan mengikuti kondisi penyebaran COVID-19 di Jakarta. Salah satu upaya yang dapat dilakukan untuk mengontrol penyebaran COVID-19 adalah dengan melakukan testing. Testing dilakukan pada populasi exposed dengan tujuan dapat mengurangi penyebaran COVID-19 di Jakarta. Kemudian menentukan kontrol optimal menggunakan Prinsip Maksimum Pontryagin dan diselesaikan secara numerik menggunakan program Matlab berdasarkan metode forward-backward sweep Runge-Kutta orde empat. Dari hasil analisis simulasi, didapat bahwa dengan melakukan testing pada populasi exposed yang mengakibatkan berkurangnya jumlah populasi exposed sebesar 99% sehingga dapat mengurangi penyebaran COVID-19 di Jakarta.]]>
<![CDATA[Optimization of fuzzy entropy on solar panel’s motor ]]>
<![CDATA[MUHAMMAD IKHWAN]]>;
<![CDATA[MARWAN RAMLI]]>;
<![CDATA[MARDLIJAH MARDLIJAH]]>
<![CDATA[ Jurnal Natural Volume 22 Number 1, February 2022 ]]>
Publisher : <![CDATA[Universitas Syiah Kuala ]]>
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DOI: 10.24815/jn.v22i1.23187
<![CDATA[Renewable energy has been in great demand by the public, even some countries have set regulations for substitution and transition from fossil energy to renewable energy. This study aims to modify the fuzzy control system with a metaheuristic method, namely fuzzy entropy. The entropy value of the fuzzy set in the previous stage becomes the basis for calculating the foot of uncertainty in the new fuzzy set. This process makes the entropy method parallel to other optimization methods that have been carried out on fuzzy control systems. The results obtained indicate that the modified fuzzy control system successfully controls the angle and angular velocity of the solar panel. The error value shown is very small and the time to reach stability is below 5 s. This is a rapid development of several previous studies. The modified system has no overshoot and steady state error below 1%. Based on these results, entropy research can be developed again by changing the fuzzy set to a more complex form.]]>
<![CDATA[Penerapan Metode Kalman Filter dalam Estimasi Harga Saham Menggunakan Model ARCH-GARCH ]]>
<![CDATA[Lusi Nur Rahmawati]]>;
<![CDATA[Mardlijah Mardlijah]]>;
<![CDATA[Amirul Hakam]]>
<![CDATA[ Jurnal Sains dan Seni ITS Vol 12, No 1 (2023) ]]>
Publisher : <![CDATA[Lembaga Penelitian dan Pengabdian Kepada Masyarakat (LPPM), ITS ]]>
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DOI: 10.12962/j23373520.v12i1.96240
<![CDATA[Saham merupakan produk pasar modal yang menjadi salah satu instrumen investasi. Banyak investor yang memilih saham sebagai instrumen investasi dikarenakan saham memberikan keuntungan yang menarik. Metode estimasi merupakan metode yang tepat bagi para investor untuk memprediksi harga saham sehingga dapat membantu mengoptimalkan keuntungannya. Penelitian ini bertujuan untuk menentukan model terbaik dari data harga saham menggunakan model ARCH-GARCH dan mendapatkan hasil estimasi harga saham menggunakan metode Kalman Filter dengan model ARCH-GARCH untuk periode selanjutnya. Adapun data harga saham yang digunakan yaitu data harga saham PT. Telkom Indonesia Tbk yang diambil dari website resmi Yahoo Finance. Data yang diambil adalah data harga saham saat penutupan (close) periode 29 Februari 2020 sampai 31 Agustus 2021. Pada data harga saham digunakan model ARIMA (Autoregressive Integrated Moving Average) dan terdeteksi terdapat unsur heteroskedastisitas, sehingga digunakan model time series ARCH-GARCH (Autoregressive Conditional Heteroskedasticity Generalized Autoregressive Conditional Heteroskedasticity). Didapatkan model terbaik yaitu GARCH (1,1) dengan model ARIMA (2,1,3). Pada penerapan metode Kalman Filter didapatkan hasil estimasi harga saham lebih akurat yaitu mendekati data aktual yang ditandai dengan nilai MAPE (Mean Absolute Percentage Error) pada GARCH-Kalman Filter lebih kecil dibandingkan nilai MAPE pada model GARCH (1,1).]]>
<![CDATA[Optimization of fuzzy entropy on solar panel’s motor ]]>
<![CDATA[MUHAMMAD IKHWAN]]>;
<![CDATA[MARWAN RAMLI]]>;
<![CDATA[MARDLIJAH MARDLIJAH]]>
<![CDATA[ Jurnal Natural Volume 22 Number 1, February 2022 ]]>
Publisher : <![CDATA[Universitas Syiah Kuala ]]>
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DOI: 10.24815/jn.v22i1.23187
<![CDATA[Renewable energy has been in great demand by the public, even some countries have set regulations for substitution and transition from fossil energy to renewable energy. This study aims to modify the fuzzy control system with a metaheuristic method, namely fuzzy entropy. The entropy value of the fuzzy set in the previous stage becomes the basis for calculating the foot of uncertainty in the new fuzzy set. This process makes the entropy method parallel to other optimization methods that have been carried out on fuzzy control systems. The results obtained indicate that the modified fuzzy control system successfully controls the angle and angular velocity of the solar panel. The error value shown is very small and the time to reach stability is below 5 s. This is a rapid development of several previous studies. The modified system has no overshoot and steady state error below 1%. Based on these results, entropy research can be developed again by changing the fuzzy set to a more complex form.]]>
