Jurnal Teknik Informatika (JUTIF)
Vol. 7 No. 5 (2026): JUTIF Volume 7, Number 5, October 2026

Benchmarking IndoBERT and Optimized Long Short-Term Memory for Sentiment Analysis on the Access by KAI Mobile Application

I Gusti Ayu Agung Mas Aristamy (Department of Informatics, Institut Bisnis dan Teknologi Indonesia, Indonesia)
I Gusti Ayu Putu Widhya Iswari (Department of Informatics, Institut Bisnis dan Teknologi Indonesia, Indonesia)
Ni Putu Suci Meinarni (Department of Informatics, Institut Bisnis dan Teknologi Indonesia, Indonesia)
Ni Wayan Wardani (Department of Information and Communication System, Okayama University, Japan)



Article Info

Publish Date
10 Oct 2026

Abstract

PT Kereta Api Indonesia (Persero), or PT KAI, is a key public transportation provider in Indonesia whose service quality significantly influences public perception. The proliferation of digital platforms allows users to voice their opinions on PT KAI’s services, rendering sentiment analysis a vital tool for evaluating public satisfaction. This study analyzes public sentiment toward PT KAI by benchmarking the performance of Long Short-Term Memory (LSTM) and IndoBERT models. We collected 82,044 user reviews from various digital platforms including X (formerly Twitter), Instagram, TikTok, YouTube, Facebook, and Google Play Store specifically focusing on the “Access by KAI” application. Data labeling utilized the InSet Lexicon, and the dataset was partitioned into training and testing sets at an 80:20 ratio. During the initial training phase, the LSTM model exhibited overfitting, evidenced by a significant disparity between training and validation performance. To mitigate this, several optimization strategies were implemented, including architecture simplification, dropout, L2 regularization, and early stopping. Post optimization, the LSTM model achieved 95.98% accuracy, while IndoBERT reached 96.15%. Although the 0.17% performance gap is marginal, IndoBERT demonstrated superior stability in processing informal social media registers without extensive normalization. Practically, this suggests that IndoBERT is more robust for real-time monitoring systems where data variety is high, whereas LSTM remains a viable, lightweight alternative for resource-constrained environments. This research contributes to computational linguistics by providing a robust performance comparison of transformer-based vs. recurrent architectures in processing the informal registers of the Indonesian language.

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Journal Info

Abbrev

jurnal

Publisher

Subject

Computer Science & IT

Description

Jurnal Teknik Informatika (JUTIF) is an Indonesian national journal, publishes high-quality research papers in the broad field of Informatics, Information Systems and Computer Science, which encompasses software engineering, information system development, computer systems, computer network, ...