Institut Teknologi Nasional Bandung

AI-BASED AUTOMATED ASSESSMENT FOR ENGLISH SPEAKING PROFICIENCY

Nur Fitrianti F., S.Kom., M.T, Corry Caromawati, S.S., M.A., Ph.D., Sofia Umaroh, S.Pd.,M.T. Wahyudi

Kemampuan berkomunikasi dalam bahasa Inggris yang masih rendah di Indonesia (peringkat 80 dalam English Proficiency Index 2024) disebabkan oleh faktor kompleks, termasuk metode pembelajaran tradisional yang kurang melatih penggunaan aktif bahasa, ket...

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AI-BASED AUTOMATED ASSESSMENT FOR ENGLISH SPEAKING PROFICIENCY

Nur Fitrianti F., S.Kom., M.T, Corry Caromawati, S.S., M.A., Ph.D., Sofia Umaroh, S.Pd.,M.T. Wahyudi

Kemampuan berkomunikasi dalam bahasa Inggris yang masih rendah di Indonesia (peringkat 80 dalam English Proficiency Index 2024) disebabkan oleh faktor kompleks, termasuk metode pembelajaran tradisional yang kurang melatih penggunaan aktif bahasa, ketimpangan kualitas pendidikan, dan penilaian (assessment) yang tidak autentik. Tes konvensional sering gagal mengukur language proficiency secara holistik (akurasi, kompleksitas, kefasihan) sesuai standar CEFR, serta menghadapi masalah rater fatigue dan bias. Meskipun tes berbasis komputer seperti TOEFL iBT atau Duolingo tersedia, harganya mahal dan tidak menyediakan umpan balik pembelajaran.

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NEPTUNE: kNowledge rEPresentaTion Using kNowlEdge Graph and Ontology

Sofia Umaroh, Kurnia Ramadhan Putra, Muhammad Hilmy Aiman, Bennart Dem Gunawaan

The needs for more structured and effective ways to represent the profiles of researchers (Huynh, 2014). Research collaboration has become increasingly vital for higher education institutions (Lima, et. al., 2021; Bravo, 2019). Identify potential col...

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NEPTUNE: kNowledge rEPresentaTion Using kNowlEdge Graph and Ontology

Sofia Umaroh, Kurnia Ramadhan Putra, Muhammad Hilmy Aiman, Bennart Dem Gunawaan

The needs for more structured and effective ways to represent the profiles of researchers (Huynh, 2014). Research collaboration has become increasingly vital for higher education institutions (Lima, et. al., 2021; Bravo, 2019). Identify potential collaborators is difficult especially for young researchers (Bravo, 2019). Proposed an ontology based model using semantic language of Web Ontology Language (OWL) enriched by transforming the populated ontology into a knowledge graph using Neo4J. Predict potential collaborations between researchers using content-based and graph-based similarity measures.

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TRIPLE EXPONENTIAL SMOOTHING AND RANDOM FOREST ALGORITHMS FOR A HYBRID RISK FORECASTING BY USING WEIGHTED EVENT DATA

R. Budiraharjo, Mira Musrini B., Carissa Adnyana Putri R.

Risk forecasting plays a crucial role in various fields, ranging from finance to environmental management. This research proposes a novel approach that combines the Triple Exponential Smoothing (TES) method and the Random Forest (RF) algorithm to ach...

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TRIPLE EXPONENTIAL SMOOTHING AND RANDOM FOREST ALGORITHMS FOR A HYBRID RISK FORECASTING BY USING WEIGHTED EVENT DATA

R. Budiraharjo, Mira Musrini B., Carissa Adnyana Putri R.

Risk forecasting plays a crucial role in various fields, ranging from finance to environmental management. This research proposes a novel approach that combines the Triple Exponential Smoothing (TES) method and the Random Forest (RF) algorithm to achieve more accurate and reliable risk forecasting. TES is highly effective in predicting seasonality and trends in time-series data, while RF excels in handling complex non-linear relationships and mitigating model overfitting. By integrating these two methods, the proposed hybrid model aims to leverage the strengths of each method to enhance the accuracy and performance of risk prediction. This research represents an effort to improve the performance of the seventh step in the Improved Multi-Attribute Risk Assessment (IMARA) method, which is risk forecasting. The experiments in this study utilize a dataset from PT Terminal Peti Kemas Surabaya to evaluate the performance of the proposed approach. The results of this research are expected to demonstrate an improvement in the accuracy and performance of risk prediction compared to the risk prediction performance generated by the TES and RF methods when applied individually, especially in dealing with complex data patterns and dynamic risk factors. This research uses three scenarios for combining TES and RF to obtain the highest accuracy in risk forecasting. The results from the first phase of the experiments showed that Scenario 3 yields slightly better accuracy compared to the two other scenarios.

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PENGEMBANGAN KENDARAAN LISTRIK TAKTIS SERGAP SENYAP UNTUK MENDUKUNG INDUSTRI PERTAHANAN NASIONAL

Institut Teknologi Nasional Bandung – 2021

Mengembangkan kendaraan listrik taktis (rantis) untuk keperluan militer yang senyap, handal, dan mampu menerobos halangan, dilengkapi dengan sistem pelontar peluru berbasis pneumatik.

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PENGEMBANGAN KENDARAAN LISTRIK TAKTIS SERGAP SENYAP UNTUK MENDUKUNG INDUSTRI PERTAHANAN NASIONAL

Institut Teknologi Nasional Bandung – 2021

Mengembangkan kendaraan listrik taktis (rantis) untuk keperluan militer yang senyap, handal, dan mampu menerobos halangan, dilengkapi dengan sistem pelontar peluru berbasis pneumatik.

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ANALISA KARAKTERISASI MATERIAL PRODUK SLIDE PIECE CVT BERBAHAN KOMPOSIT BERPENGUAT SERAT NANAS DENGAN FRAKSI VOLUME 10%

Ahmad Dzilfairuz Zaidan, Alfan Ekajati Latief, Nuha Desi Anggraeni

Penelitian ini menganalisis komposit berbahan polypropylene high impact (PPHI) yang diperkuat dengan serat nanas (volume fraksi 10%) untuk digunakan sebagai komponen slide piece CVT (Continuously Variable Transmission) pada kendaraan bermotor.

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ANALISA KARAKTERISASI MATERIAL PRODUK SLIDE PIECE CVT BERBAHAN KOMPOSIT BERPENGUAT SERAT NANAS DENGAN FRAKSI VOLUME 10%

Ahmad Dzilfairuz Zaidan, Alfan Ekajati Latief, Nuha Desi Anggraeni

Penelitian ini menganalisis komposit berbahan polypropylene high impact (PPHI) yang diperkuat dengan serat nanas (volume fraksi 10%) untuk digunakan sebagai komponen slide piece CVT (Continuously Variable Transmission) pada kendaraan bermotor.

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PERFORMANCE AND EMISSION OF DIESEL ENGINE FUELLED BY COMMERCIAL BIO-DIESEL FUELS IN INDONESIA

Tarsisius Kristiyadi, Diki Ismail Permana, Muhammad Pramuda Nugraha Sirodz, Encu Saefudin, Istvan Farkas

The performance and emission of a small diesel engine fuelled by commercial diesel fuel in Indonesia are present in this paper. Various commercial diesel fuels in Indonesia are produced and marketed by Pertamina. As the largest oil company in In...

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PERFORMANCE AND EMISSION OF DIESEL ENGINE FUELLED BY COMMERCIAL BIO-DIESEL FUELS IN INDONESIA

Tarsisius Kristiyadi, Diki Ismail Permana, Muhammad Pramuda Nugraha Sirodz, Encu Saefudin, Istvan Farkas

The performance and emission of a small diesel engine fuelled by commercial diesel fuel in Indonesia are present in this paper. Various commercial diesel fuels in Indonesia are produced and marketed by Pertamina. As the largest oil company in Indonesia, Pertamina has developed various diesel fuels, namely Solar, Biosolar (B30), Dexlite, and Pertadex. This study explains in more detail the performance, fuel consumption, and emission produced by the four types of fuels, and they were investigated experimentally using a single-cylinder diesel engine at various engine speeds, from 1,000 rpm to 4,500 rpm. The result shows the engine fuelled by Pertadex generates the highest power and torque, while the lowest is generated by the Biosolar fuelled engine. The maximum torque and power generated by the Pertadex fuelled engine are about 25.5 Nm and 7200 W, respectively. The engine fuelled by Pertadex has the lowest brake specific fuel consumption (BSFC) of 0.3037 kg·kW·h, compared to the engines fuelled by the Dexlite, Solar, and Biosolar fuels, with values around 0.3127, 0.3215, and 0.3338 kg·kW·h, respectively. At the same time, the measurement of gas emissions, including CO2, CO, NOx, and HC was conducted simultaneously.

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COMPETITION OF GRAVITY AND VISCOUS FORCES IN MISCIBLE VERTICAL DISPLACEMENT IN A THREE-DIMENSIONAL POROUS MEDIUM

Mohammad Azis Mahardika ORCID logo ; Yun She (佘云) ORCID logo ; Tomotaka Koe (鴻江智任); Anindityo PatmonoajiCorresponding Author ORCID logo ; Muhammad Nasir ORCID logo ; Shintaro Matsushita (松下真太郎); Tetsuya Suekane (末包哲也)

When viscosity and density contrast exist in the vertical miscible displacement in porous media between two fluids, the interplay between the viscous force and gravity determines the interface stability. Two stability criteria are derived to determin...

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COMPETITION OF GRAVITY AND VISCOUS FORCES IN MISCIBLE VERTICAL DISPLACEMENT IN A THREE-DIMENSIONAL POROUS MEDIUM

Mohammad Azis Mahardika ORCID logo ; Yun She (佘云) ORCID logo ; Tomotaka Koe (鴻江智任); Anindityo PatmonoajiCorresponding Author ORCID logo ; Muhammad Nasir ORCID logo ; Shintaro Matsushita (松下真太郎); Tetsuya Suekane (末包哲也)

When viscosity and density contrast exist in the vertical miscible displacement in porous media between two fluids, the interplay between the viscous force and gravity determines the interface stability. Two stability criteria are derived to determine the interface stability. Hill's and Dumore's stability criteria are used to determine the interface stability of the sharp and diffused interface, respectively. In this study, we visualized the crossover between unstable displacement and stable displacement for a vertical displacement in porous media using microfocused x-ray computed tomography. The experiments were divided into four possible configurations: (1) unconditionally stable (gravitationally stable-viscously stable), (2) unconditionally unstable (gravitationally unstable-viscously unstable), (3) conditionally stable (gravitationally stable-viscously unstable), and (4) conditionally stable (gravitationally unstable, viscously stable). The structure of the displacement interface was visualized for the critical velocity ratio (V/Vc) in the range of 0.5–11.9. In the conditionally stable configurations 3 and 4, a crossover between stable and unstable displacements was observed. We found that Dumore's stability criterion is more appropriate for predicting interface stability than Hill's stability criterion. Viscous fingering occurs in configuration 3 when V/Vc is higher than Dumore's critical velocity, whereas gravity fingering occurs in configuration 4 when V/Vc is lower than Dumore's critical velocity. Similar events in two-dimensional experiments, such as tip-splitting, shielding, and coalescence, were also observed three-dimensionally. The significant changes in the mixing length and sweep efficiency signify the crossover between the stable and unstable displacements.

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CRACK OF A FIRST STAGE BLADE IN A STEAM TURBINE

M. Nurbanasari a, Abdurrachim

The failure of the first stage blade in a steam turbine of 55 MW was investigated. The blade was made of 17-4 PH stainless steel and has been used for 12 years before failure. The current work aims to find out the main cause of the first stage b...

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CRACK OF A FIRST STAGE BLADE IN A STEAM TURBINE

M. Nurbanasari a, Abdurrachim

The failure of the first stage blade in a steam turbine of 55 MW was investigated. The blade was made of 17-4 PH stainless steel and has been used for 12 years before failure. The current work aims to find out the main cause of the first stage blade failure. The methods for investigation were metallurgical analysis, chemical composition test, and hardness measurement. The result showed that there was no evidence the blade failure was due to material. The damage found on the blade namely crack on the blade root. Two locations of the crack observed at the blade root, which was at the tang and the fillet, with different failure modes. In general, the damage of the blade was started by the corrosion occurred on the blade root. The crack at the blade root tang was due to corrosion fatigue and the crack occurred at the blade root fillet owing to stress corrosion cracking.

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UTILIZATION OF SMALL SOLAR ORC INTEGRATED WITH PHASE CHANGE MATERIAL IN INDONESIA CONDITION

Diki Ismail Permana, Mohammad Azis Mahardika, Dani Rusirawan, István Farkas

The Indonesian government is attempting to boost the use of the renewable energy, with a target around 25 GW in 2025 and 149 GW in 2050. Specifically, in the solar energy usage sector, Indonesia has a daily total of around 3.6 to 6.5 kWh/m2 ...

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UTILIZATION OF SMALL SOLAR ORC INTEGRATED WITH PHASE CHANGE MATERIAL IN INDONESIA CONDITION

Diki Ismail Permana, Mohammad Azis Mahardika, Dani Rusirawan, István Farkas

The Indonesian government is attempting to boost the use of the renewable energy, with a target around 25 GW in 2025 and 149 GW in 2050. Specifically, in the solar energy usage sector, Indonesia has a daily total of around 3.6 to 6.5 kWh/m2 and annually total around 1314 to 2191 kWh/m2. It makes a proper location for building a solar energy employing an organic Rankine cycle (ORC). In this study, the author examines how much power and efficiency solar collectors produce using energy, exergy, and environmental analysis with different working fluids (R245fa, R134a, Propane, R32, R410a) by taking advantage of the weather in Bandung, Indonesia to provide backup electricity during high-load hours. Because solar heat is the only heat source in this study, the selection, sizing, and methods of thermal energy storage (TES) with various phase change materials (PCM) were analysed. The study found that in July 2021, R134a produced the highest power around 685 W.h/day and R245fa is produced the highest efficiency of 7.45 %. Meanwhile, to store the heat that will be used, inorganic PCM was chosen as the TES-evaporator material for low melting temperature (~313 K) and high volumetric heating (~389 MJ/m3) with capacity of 300 L, which can store heat optimally and can running the ORC for about 500 W.

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