Перегляд за Автор "Stetsenko, Inna V."

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    Detection Method of Fraudulent Payment Transaction Based on C-Score Metric
    (National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2025) Korynetskyi, Dmytro; Stetsenko, Inna V.
    Fraud detection for payment transactions is a cost-sensitive task, as the costs associated with misclassification – such as missing a fraudulent transaction or incorrectly blocking a legitimate one – can vary significantly depending on business priorities. Traditional evaluation metrics, particularly the F1-score, ignore this asymmetry, creating a need for more flexible approaches. This research focuses on developing a method for building adaptive, cost-sensitive fraud detection systems. The aim is to develop a method that enables the practical application of the cost-sensitive C-score metric to configure a multi-level decision logic. The paper also presents a possible software architecture for its implementation. The proposed two-phase method (offline calibration and online scoring) uses the C-score metric to determine multiple decision thresholds corresponding to different business scenarios. Its validation was conducted on the public “Credit Card Fraud Detection” dataset using the XGBoost algorithm. The Synthetic Minority Over-sampling Technique (SMOTE) was applied to overcome the severe class imbalance in the data, and a comparison was made against the traditional F1-score-based approach. The experimental results showed that the proposed approach allows for the identification of two distinct thresholds from a single classifier. The first threshold ensures high precision, making it suitable for automated blocking of payment transactions with minimal false positives. The second threshold, focused on high recall, enables the selection of suspicious payment transactions for subsequent manual review. It was also confirmed that the SMOTE significantly contributed the model's class separation ability, thereby increasing the reliability of calibrating these thresholds. Based on the method, a practical blueprint for a service-oriented architecture is proposed for creating flexible and configurable anti-fraud systems.
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    Environment for Tuning Parameters of a Multithreaded Program Developed Using a Dependency Graph
    (National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2025) Nesterenko, Kostiantyn; Stetsenko, Inna V.
    With the advent of multi-core central processors, multithreading has become the most widespread practice for improving program execution performance. However, the development of a multithreaded program remains a rather complex process. To simplify this process and enhance the performance of the resulting program, various methods for managing thread-based execution are often employed.One such method is the method ofmanaging the execution of tasks of a multithreaded program according to a given dependency graph. This method significantly reduces the resource intensity of program development and increases program performance by employing a lockless approach to multithreaded programming.Nevertheless, the challenge of efficient utilization of computational resources remains relevant and can only be addressed through the careful design of parallel computations. In particular, identifying the configuration parameters for a multithreaded program that ensure optimal resource utilization is a resource-intensive and complex task, even for highly qualified specialists.This study examines existing approaches to tuning the parameters of multithreaded programs to achieve the mostefficient execution. It proposes the use of an environment for tuning multithreaded program parameters based on the method of managing the execution of tasks of a multithreaded program according to a given dependency graph. The accuracy of the resource efficiency metrics obtained through this environment was experimentally validated. A practical example demonstrates the application of the environment in the development of a multithreaded program. The use of the environment also facilitates the configuration process of multithreaded program parameters