Tai-Won Um

Tai-Won Um

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

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

Representative Publications

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24 May 2018 in IEEE Transactions on Sustainable Computing
Verified
Journal Article
Open access
Upul JayasingheUpul Jayasinghe
Upul Jayasinghe
Gyu Myoung LeeGyu Myoung Lee
Gyu Myoung Lee
TUTai-Won Um
Tai-Won Um
QSQi Shi
Qi Shi
The Internet of Things has facilitated access to a large volume of sensitive information on each participating object in an ecosystem. This imposes many threats ranging from the risks of data management to the potential discrimination enabled by data analytics over delicate information such as locations, interests, and activities. To address these issues, the concept of trust is introduced as an important role in supporting both humans and services to overcome the perception of uncertainty and risks before making any decisions. However, establishing trust in a cyber world is a challenging task due to the volume of diversified influential factors from cyber-physical-systems. Hence, it is essential to have an intelligent trust computation model that is capable of generating accurate and intuitive trust values for prospective actors. Therefore, in this paper, a quantifiable trust assessment model is proposed. Built on this model, individual trust attributes are calculated numerically. Moreover, a novel algorithm based on machine learning principles is devised to classify the extracted trust features and combine them to produce a final trust value to be used for decision making. Finally, our model's effectiveness is verified through a simulation. The results show that our method has advantages over other aggregation methods.

7 March 2019 in IEEE Transactions on Information Forensics and Security
Verified
Journal Article
Open access
NTNguyen Binh Truong
Nguyen Binh Truong
Gyu Myoung LeeGyu Myoung Lee
Gyu Myoung Lee
TUTai-Won Um
Tai-Won Um
MMMichael Mackay
Michael Mackay
Mobile Crowd-Sensing (MCS) has appeared as a prospective solution for large-scale data collection, leveraging built-in sensors and social applications in mobile devices that enables a variety of Internet of Things (IoT) services. However, the human involvement in MCS results in a high possibility for unintentionally contributing corrupted and falsified data or intentionally spreading disinformation for malevolent purposes, consequently undermining IoT services. Therefore, recruiting trustworthy contributors plays a crucial role in collecting highquality data and providing better quality of services while minimizing the vulnerabilities and risks to MCS systems. In this article, a novel trust model called Experience-Reputation (E-R) is proposed for evaluating trust relationships between any two mobile device users in an MCS platform. To enable the E-R model, virtual interactions among the users are manipulated by considering an assessment of the quality of contributed data from such users. Based on these interactions, two indicators of trust called Experience and Reputation are calculated accordingly. By incorporating the Experience and Reputation trust indicators (TIs), trust relationships between the users are established, evaluated and maintained. Based on these trust relationships, a novel trust-based recruitment scheme is carried out for selecting the most trustworthy MCS users to contribute to data sensing tasks. In order to evaluate the performance and effectiveness of the proposed trust-based mechanism as well as the E-R trust model, we deploy several recruitment schemes in an MCS testbed which consists of both normal and malicious users. The results highlight the strength of the trust-based scheme as it delivers better quality for MCS services while being able to detect malicious users. We believe that the trust-based user recruitment offers an effective capability for selecting trustworthy users for various MCS systems and, importantly, the proposed mechanism is practical to deploy in the real world.

1 March 2021 in Symmetry
Verified
Journal Article
Open access
PDF file
MWMuhammad Waleed
Muhammad Waleed
TUTai-Won Um
Tai-Won Um
TKTariq Kamal
Tariq Kamal
Syed Muhammad UsmanSyed Muhammad Usman
Syed Muhammad Usman
In this paper, we apply the multi-class supervised machine learning techniques for classifying the agriculture farm machinery. The classification of farm machinery is important when performing the automatic authentication of field activity in a remote setup. In the absence of a sound machine recognition system, there is every possibility of a fraudulent activity taking place. To address this need, we classify the machinery using five machine learning techniques—K-Nearest Neighbor (KNN), Support Vector Machine (SVM), Decision Tree (DT), Random Forest (RF) and Gradient Boosting (GB). For training of the model, we use the vibration and tilt of machinery. The vibration and tilt of machinery are recorded using the accelerometer and gyroscope sensors, respectively. The machinery included the leveler, rotavator and cultivator. The preliminary analysis on the collected data revealed that the farm machinery (when in operation) showed big variations in vibration and tilt, but observed similar means. Additionally, the accuracies of vibration-based and tilt-based classifications of farm machinery show good accuracy when used alone (with vibration showing slightly better numbers than the tilt). However, the accuracies improve further when both (the tilt and vibration) are used together. Furthermore, all five machine learning algorithms used for classification have an accuracy of more than 82%, but random forest was the best performing. The gradient boosting and random forest show slight over-fitting (about 9%), but both algorithms produce high testing accuracy. In terms of execution time, the decision tree takes the least time to train, while the gradient boosting takes the most time.

26 February 2020 in Remote Sensing
Verified
Journal Article
Open access
PDF file
MWMuhammad Waleed
Muhammad Waleed
TUTai-Won Um
Tai-Won Um
AKAftab Khan
Aftab Khan
UKUmair Khan
Umair Khan
Olive cultivation over the past few years has spread across Mediterranean countries with Spain being the world’s largest olive producer among them. Because olives are a major part of the economy for such countries keeping records of their tree count and crop yield is of high significance. Manual counting of trees over such large areas is humanly infeasible. To address this problem, we propose an automatic method for the detection and enumeration of olive trees. The algorithm is a multi-step classification system comprising pre-processing, image segmentation, feature extraction, and classification. RGB satellite images were acquired from the Spanish territory and pre-processed to suppress the additive noise. The region of interest was then segmented from the pre-processed images using K-Means segmentation, through which statistical features were extracted and classified. Promising results were achieved for all classifiers, namely Naive Bayesian, Support Vector Machines (SVMs), Random Forest and Multi-Layer Perceptrons (MLPs), at various division ratios of data samples. In a comparison of all the classification algorithms, Random Forest outperformed the rest by an overall accuracy of 97.5% at the division ratio of 70 to 30 for training to testing.

20 June 2024 in IEEE Access
Verified
Journal Article
Open access
RMRuturaj Mahadshetti
Ruturaj Mahadshetti
Jinsul KimJinsul Kim
Jinsul Kim
TUTai-Won Um
Tai-Won Um
Traffic sign detection (TSD) is crucial for real-world applications like driverless vehicles, intelligent driver-assistance systems, and traffic management. Recent advancements in TSD have demonstrated promising outcomes. Nonetheless, challenges persist in terms of speed, accuracy, memory consumption, the capability of the backbone to generate features, and computational cost, especially in handling diverse traffic sign characteristics. To overcome these challenges, we propose Sign-YOLO (You Only Look Once), a novel attention-based one-stage method that integrates YOLOv7 with the squeeze-and-excitation (SE) model and special attention mechanism. Sign-YOLO enhances the feature representation capacity of the model in the presence of variations in traffic sign sizes. The SE block adjusts channel-specific feature responses by actively considering the relationships between channels. By selectively focusing on relevant features, the attention mechanism helps the model better capture and understand the distinctive characteristics of traffic signs, thereby improving detection accuracy. Sign-YOLO effectively reduces the computational cost and memory consumption; further, it effectively enriches the robustness of extracted features. The proposed approach enables the model to allocate more attention to relevant regions of the input, thereby reducing the impact of size discrepancies and contributing to the overall robustness of the system. The experimental findings highlight the success of Sign-YOLO in TSD tasks. Our proposed method exhibits cutting-edge performance on the German Traffic Signs Detection Benchmark (GTSDB) dataset, simultaneously achieving a 98% reduction in model size and memory consumption. Sign-YOLO attains a 99.10% mean average precision (mAP) on the GTSDB dataset. In comparison to both two- and one-stage detectors, our approach exhibits an improvement of 3.33%. The proposed approach is the swiftest and most lightweight framework in terms of memory usage, making it the ideal option for implementation in real-time applications.

28 July 2023 in Sensors
Verified
Journal Article
Open access
PDF file
MWMuhammad Waleed
Muhammad Waleed
TKTariq Kamal
Tariq Kamal
TUTai-Won Um
Tai-Won Um
AHAbdul Hafeez
Abdul Hafeez
BHBilal Habib
Bilal Habib
KSKnud Erik Skouby
Knud Erik Skouby
The remote monitoring of patients using the internet of things (IoT) is essential for ensuring continuous observation, improving healthcare, and decreasing the associated costs (i.e., reducing hospital admissions and emergency visits). There has been much emphasis on developing methods and approaches for remote patient monitoring using IoT. Most existing frameworks cover parts or sub-parts of the overall system but fail to provide a detailed and well-integrated model that covers different layers. The leverage of remote monitoring tools and their coupling with health services requires an architecture that handles data flow and enables significant interventions. This paper proposes a cloud-based patient monitoring model that enables IoT-generated data collection, storage, processing, and visualization. The system has three main parts: sensing (IoT-enabled data collection), network (processing functions and storage), and application (interface for health workers and caretakers). In order to handle the large IoT data, the sensing module employs filtering and variable sampling. This pre-processing helps reduce the data received from IoT devices and enables the observation of four times more patients compared to not using edge processing. We also discuss the flow of data and processing, thus enabling the deployment of data visualization services and intelligent applications.