INVOTEK: Jurnal Inovasi Vokasional dan Teknologi

Application of K-Means Data Mining to Measure the Level of Satisfaction of KITA Car Driving Course

Shelvina Ayu Wardani, Ruri Ashari Dalimunthe, Abdulkarim Syahputra — Sat, 09 Aug 2025 11:22:33 +0000

KITA Driving Course, located in Kisaran, North Sumatra, faces challenges in maintaining service quality amidst increasing student enrollment. Despite operating since 2013, the institution lacks a structured, data-driven evaluation system to assess student satisfaction. This study applies a quantitative descriptive approach using the K-Means clustering algorithm to classify student satisfaction levels. Data were collected from 100 respondents through a questionnaire based on the five SERVQUAL dimensions: tangibles, reliability, responsiveness, assurance, and empathy. The K-Means algorithm grouped the satisfaction data into three categories: highly satisfied, satisfied, and dissatisfied. The majority of students were classified as satisfied (18 students), followed by highly satisfied (11 students), and dissatisfied (10 students). The findings indicate that the K-Means algorithm provides valuable insights into student satisfaction patterns, enabling targeted service improvements. The analysis also reveals that responsiveness and assurance were key areas of dissatisfaction, suggesting that instructor response time and safety assurance should be prioritized. These insights can help improve service strategies and can be adapted by other educational institutions for quality optimization through data analysis.

Evaluation of the Impact of Governor-less Control on the Transient Response of Hydraulic Load Frequency Control Systems

Heru Dibyo Laksono, Dhea Rahmadani Putri, Mumuh Muharam — Mon, 11 Aug 2025 15:40:49 +0000

This study evaluates the transient performance of a hydraulic Load Frequency Control (LFC) system configured with a single controller and without a governor. The analysis focuses on rise time, peak time, settling time, and overshoot, using various controllers including PI, PD, PID, PDF, and PIDF. Simulation results indicate that eliminating the governor significantly enhances system responsiveness and reduces overshoot, particularly when using the PDF controller. Quantitative analysis shows that the PDF controller achieves 85% faster rise time (0.101s vs 0.607s for P controller) and maintains system stability with minimal overshoot (1.765% for PID vs 59.263% for P controller). This configuration enables for a more direct and efficient control response to load fluctuations, improving system stability. Thus, employing a single controller without a governor presents a promising alternative for frequency regulation in hydraulic LFC systems under dynamic load conditions. The findings of this study offer valuable insights for optimizing controller selection and configuration in practical implementations, providing guidance for engineers and researchers to enhance grid reliability, operational efficiency, and stability in various real-world hydraulic power system scenarios.

CFD Simulation of Pipe Joints Using SimScale: Analysis of the Effect of Different Inlet Velocities on Water Fluid Flow

Haning Hasbiyati, Audha Fitrah Aulina — Mon, 11 Aug 2025 17:19:28 +0000

This study aims to analyze the effect of variations in inlet velocity on fluid flow patterns at tee-junction pipe connections using numerical simulations based on Computational Fluid Dynamics (CFD). The SimScale platform was used because it supports cloud-based processing and integration with OpenFOAM solvers. The tee connection model is designed in three dimensions, with the main and branch pipe dimensions each having a diameter of 100 mm. The merging process uses the parametric hexagonal method and local refinement in the joint area to accurately capture turbulent phenomena. Simulations were performed under incompressible and isothermal flow conditions with a standard k–ε turbulence model, using water fluid and the SIMPLE algorithm. The inlet velocity consists of 2 variations A (V_I = 1 m/s, V₂ = -1 m/s) and variation B (V₁ = -1.5 m/s, V₂ = -3 m/s). Simulation results show that increasing the inlet velocity results in a more turbulent flow, characterized by an increase in the turbulent kinematic viscosity, specific dissipation rate, and turbulent kinetic energy. Conversely, low velocities indicate higher pressure accumulation due to flow resistance. These findings indicate that inlet velocity variations significantly affect flow characteristics, requiring attention in system design to maintain long-term operational efficiency and reliability.

Performance Analysis of FRP Reinforced Concrete After Corrosion Damage

Achmad Zultan Mansur — Sun, 17 Aug 2025 17:03:40 +0000

Corrosion in bridge girder beams frequently leads to significant structural damage, such as concrete spalling and reduced reinforcement, which directly impacts the bending capacity. This study experimentally assessed the efficacy of a combined repair strategy of grouting and Glass Fiber Reinforced Polymer (GFRP) reinforcement on simulated damaged reinforced concrete beams. Twelve beams were tested with various repair configurations, including a standalone grouting repair and a combination of grouting with GFRP in strip and U-wrap configurations. The primary objective was to comprehensively evaluate the enhanced flexural capacity and failure modes of these repaired beams. The results indicated that GFRP reinforcement, particularly the U-wrap configuration, significantly improved the beams' flexural capacity. Beams with the GFRP U-wrap configuration achieved an average maximum load of 32.50 kN, surpassing the control beam's 29.74 kN by 9.27%. Conversely, a standalone grouting repair drastically decreased the load capacity to 14.49 kN, highlighting its inefficiency in strength restoration. Debonding failure at the grout-concrete interface was identified as the primary cause of this reduction. The U-wrap configuration outperformed the strip configuration, likely due to its enhanced shear resistance and confinement. The GFRP strain analysis showed linear behavior at low loads but significant deviations at higher loads, which indicates debonding. All beams exhibited a dominant flexural cracking failure mode, with the addition of GFRP reducing the number of cracks. In conclusion, the combined grouting and GFRP reinforcement, especially the U-wrap configuration, proved to be an effective strategy for repairing damaged RC beams. However, achieving strong adhesion between the repair materials and the concrete is crucial to prevent debonding and optimize structural performance. Further research on enhancing adhesion and optimizing GFRP configurations is recommended.