Jihwan Lee

Prof. Jihwan Lee

orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 July 2021 in Sensors
Verified
Journal Article
Open access
PDF file
DKDonghyun Kim
Donghyun Kim
GAGian Antariksa
Gian Antariksa
MHMelia Putri Handayani
Melia Putri Handayani
SLSangbong Lee
Sangbong Lee
JLJihwan Lee
Jihwan Lee
In this study, we proposed a data-driven approach to the condition monitoring of the marine engine. Although several unsupervised methods in the maritime industry have existed, the common limitation was the interpretation of the anomaly; they do not explain why the model classifies specific data instances as an anomaly. This study combines explainable AI techniques with anomaly detection algorithm to overcome the limitation above. As an explainable AI method, this study adopts Shapley Additive exPlanations (SHAP), which is theoretically solid and compatible with any kind of machine learning algorithm. SHAP enables us to measure the marginal contribution of each sensor variable to an anomaly. Thus, one can easily specify which sensor is responsible for the specific anomaly. To illustrate our framework, the actual sensor stream obtained from the cargo vessel collected over 10 months was analyzed. In this analysis, we performed hierarchical clustering analysis with transformed SHAP values to interpret and group common anomaly patterns. We showed that anomaly interpretation and segmentation using SHAP value provides more useful interpretation compared to the case without using SHAP value.

1 January 2022 in Journal of Petroleum Science and Engineering
Verified
Journal Article
Closed access
GAGian Antariksa
Gian Antariksa
RMRadhi Muammar
Radhi Muammar
JLJihwan Lee
Jihwan Lee

16 February 2024 in Sustainability
Verified
Journal Article
Open access
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NJNayoung Jeong
Nayoung Jeong
JLJihwan Lee
Jihwan Lee
In this study, we employed ChatGPT, an advanced large language model, to analyze hotel reviews, focusing on aspect-based feedback to understand service failures in the hospitality industry. The shift from traditional feedback analysis methods to natural language processing (NLP) was initially hindered by the complexity and ambiguity of hotel review texts. However, the emergence of ChatGPT marks a significant breakthrough, offering enhanced accuracy and context-aware analysis. This study presents a novel approach to analyzing aspect-based hotel complaint reviews using ChatGPT. Employing a dataset from TripAdvisor, we methodically identified ten hotel attributes, establishing aspect–summarization pairs for each. Customized prompts facilitated ChatGPT’s efficient review summarization, emphasizing explicit keyword extraction for detailed analysis. A qualitative evaluation of ChatGPT’s outputs demonstrates its effectiveness in succinctly capturing crucial information, particularly through the explicitation of key terms relevant to each attribute. This study further delves into topic distributions across various hotel market segments (budget, midrange, and luxury), using explicit keyword analysis for the topic modeling of each hotel attribute. This comprehensive approach using ChatGPT for aspect-based summarization demonstrates a significant advancement in the way hotel reviews can be analyzed, offering deeper insights into customer experiences and perceptions.

6 March 2019 in Sustainability
Verified
Journal Article
Open access
PDF file
MKMin-Kyu Kwon
Min-Kyu Kwon
JLJihwan Lee
Jihwan Lee
YHYoo Suk Hong
Yoo Suk Hong
This study aims to establish a structured business modelling methodology for successful implementation of Product-service system (PSS). The morphological analysis is applied in investigating the possible patterns of the PSS business model. To systematically collect the business model patterns, we have collected a set of predefined building blocks which can be used in business modelling. These building blocks are collected through investigation of actual PSS business model cases. By mixing and matching various building blocks, various innovative business model alternatives can be designed. To demonstrate our morphological chart, real case example of hair dryer company is illustrated. Moreover, we introduce a web-based system, which supports our business model idea generation procedure using morphological chart.

18 December 2020 in Sensors
Verified
Journal Article
Open access
PDF file
DKDonghyun Kim
Donghyun Kim
SLSangbong Lee
Sangbong Lee
JLJihwan Lee
Jihwan Lee
This study proposes an unsupervised anomaly detection method using sensor streams from the marine engine to detect the anomalous system behavior, which may be a possible sign of system failure. Previous works on marine engine anomaly detection proposed a clustering-based or statistical control chart-based approach that is unstable according to the choice of hyperparameters, or cannot fit well to the high-dimensional dataset. As a remedy to this limitation, this study adopts an ensemble-based approach to anomaly detection. The idea is to train several anomaly detectors with varying hyperparameters in parallel and then combine its result in the anomaly detection phase. Because the anomaly is detected by the combination of different detectors, it is robust to the choice of hyperparameters without loss of accuracy. To demonstrate our methodology, an actual dataset obtained from a 200,000-ton cargo vessel from a Korean shipping company that uses two-stroke diesel engine is analyzed. As a result, anomalies were successfully detected from the high-dimensional and large-scale dataset. After detecting the anomaly, clustering analysis was conducted to the anomalous observation to examine anomaly patterns. By investigating each cluster’s feature distribution, several common patterns of abnormal behavior were successfully visualized. Although we analyzed the data from two-stroke diesel engine, our method can be applied to various types of marine engine.

Verified
Journal Article
Open access
PDF file
MHMelia Putri Handayani
Melia Putri Handayani
HKHyunju Kim
Hyunju Kim
SLSangbong Lee
Sangbong Lee
JLJihwan Lee
Jihwan Lee
In the maritime industry, optimizing vessel fuel oil consumption is crucial for improving energy efficiency and reducing shipping emissions. However, effectively utilizing operational data to advance performance monitoring and optimization remains a challenge. An XGBoost Regressor model was developed using a comprehensive dataset, delivering strong predictive performance (R2 = 0.95, MAE = 10.78 kg/h). This predictive model considers operational (controllable) and environmental (uncontrollable) variables, offering insights into complex FOC factors. To enhance interpretability, SHAP analysis is employed, revealing ‘Average Draught (Aft and Fore)’ as the key controllable factor and emphasizing ‘Relative Wind Speed’ as the dominant uncontrollable factor impacting vessel FOC. This research extends to further analysis of the extremely high FOC point, identifying patterns in the Strait of Malacca and the South China Sea. These findings provide region-specific insights, guiding energy efficiency improvement, operational strategy refinement, and sea resistance mitigation. In summary, our study introduces a groundbreaking framework leveraging machine learning and SHAP analysis to advance FOC understanding and enhance maritime decision making, contributing significantly to energy efficiency and operational strategies—a substantial contribution to a responsible shipping performance assessment under tightening regulations.