Özlem Varlıklar

Dr. Özlem Varlıklar

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

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

Representative Publications

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23 February 2023 in Machines
Verified
Journal Article
Open access
PDF file
Bita GhasemkhaniBita Ghasemkhani
Bita Ghasemkhani
ÖVÖzlem Varlıklar
Özlem Varlıklar
Derya BirantDerya Birant
Derya Birant
Predictive maintenance (PdM) combines the Internet of Things (IoT) technologies with machine learning (ML) to predict probable failures, which leads to the necessity of maintenance for manufacturing equipment, providing the opportunity to solve the related problems and thus make adaptive decisions in a timely manner. However, a standard ML algorithm cannot be directly applied to a PdM dataset, which is highly imbalanced since, in most cases, signals correspond to normal rather than critical conditions. To deal with data imbalance, in this paper, a novel explainable ML method entitled “Balanced K-Star” based on the K-Star classification algorithm is proposed for PdM in an IoT-based manufacturing environment. Experiments conducted on a PdM dataset showed that the proposed Balanced K-Star method outperformed the standard K-Star method in terms of classification accuracy. The results also showed that the proposed method (98.75%) achieved higher accuracy than the state-of-the-art methods (91.74%) on the same data.

15 May 2019 in Turkish Journal of Electrical Engineering and Computer Sciences
Verified
Journal Article
Closed access
BEBuket Erşahi̇n
Buket Erşahi̇n
ÖVÖzlem Varlıklar
Özlem Varlıklar
DKDeniz KILINÇ
Deniz KILINÇ
MEMustafa Erşahi̇n
Mustafa Erşahi̇n

9 July 2024 in Animals
Verified
Journal Article
Open access
PDF file
Bita GhasemkhaniBita Ghasemkhani
Bita Ghasemkhani
ÖVÖzlem Varlıklar
Özlem Varlıklar
Yunus DoğanYunus Doğan
Yunus Doğan
SUSemih UTKU
Semih UTKU
KBKokten Ulas Birant
Kokten Ulas Birant
Derya BirantDerya Birant
Derya Birant
Federated learning is a collaborative machine learning paradigm where multiple parties jointly train a predictive model while keeping their data. On the other hand, multi-label learning deals with classification tasks where instances may simultaneously belong to multiple classes. This study introduces the concept of Federated Multi-Label Learning (FMLL), combining these two important approaches. The proposed approach leverages federated learning principles to address multi-label classification tasks. Specifically, it adopts the Binary Relevance (BR) strategy to handle the multi-label nature of the data and employs the Reduced-Error Pruning Tree (REPTree) as the base classifier. The effectiveness of the FMLL method was demonstrated by experiments carried out on three diverse datasets within the context of animal science: Amphibians, Anuran-Calls-(MFCCs), and HackerEarth-Adopt-A-Buddy. The accuracy rates achieved across these animal datasets were 73.24%, 94.50%, and 86.12%, respectively. Compared to state-of-the-art methods, FMLL exhibited remarkable improvements (above 10%) in average accuracy, precision, recall, and F-score metrics.

25 September 2020 in Turkish Journal of Electrical Engineering and Computer Sciences
Verified
Journal Article
Closed access
ÖVÖzlem Varlıklar
Özlem Varlıklar
MMMehmet MİLLİ
Mehmet MİLLİ
SLSanaz LAKESTANI
Sanaz LAKESTANI
MMMusa Milli
Musa Milli

22 January 2019 in Turkish Journal of Electrical Engineering and Computer Sciences
Verified
Journal Article
Open access
FBFatma Bozyi̇ğİt
Fatma Bozyi̇ğİt
ÖVÖzlem Varlıklar
Özlem Varlıklar
DKDeniz KILINÇ
Deniz KILINÇ

5 October 2020
Verified
Conference Paper
Closed access
ÖVÖzlem Varlıklar
Özlem Varlıklar
MMMehmet MİLLİ
Mehmet MİLLİ
SLSanaz LAKESTANI
Sanaz LAKESTANI
MMMusa Milli
Musa Milli
The increasing number of wireless sensor networks, which are used extensively in industrial areas, has led to a tremendous increase in the data obtained from the sensors. This uncontrolled increase makes it difficult for managing and storing of data. Moreover, the lack of infrastructure to ensure the integrity of meaning between the data makes it impossible to share, reuse and interpret the data by machines. These inabilities can cause some problems like cannot managing together between separate wireless sensor networks due to the subtle variations in their sensing methods, operating systems, syntax, and data structure. To address all these problems, a semantic sensor network approach has been introduced which provides a common standard for sensor data and aims to enhance their meaning. In this study, semantic model with realworld usage from sensor networks measuring some laboratory parameters is proposed. In order to evaluate the proposed system, a series of semantic queries were prepared and applied to the obtained sensor data. The results show that sensor data can be managed on a common infrastructure using ontologies.