http://repository.enu.kz/handle/enu/19147 2026-04-03T23:18:16Z 2026-04-03T23:18:16Z Yerzhan, Assel Nakisbekova, Balausa Manbetova, Zhanat Boykachev, Pavel Imankul, Manat Dzhanuzakova, Raushan Shedreyeva, Indira Karnakova, Gaini http://repository.enu.kz/handle/enu/30649 2026-03-25T19:00:59Z 2024-01-01T00:00:00Z

Using modified Chebyshev functions for approximation in 5G technologies Yerzhan, Assel; Nakisbekova, Balausa; Manbetova, Zhanat; Boykachev, Pavel; Imankul, Manat; Dzhanuzakova, Raushan; Shedreyeva, Indira; Karnakova, Gaini This research addresses the critical challenge of broadband matching in radio engineering, focusing on enhancing phase-frequency response (PFC) linearity across wide frequency bands. A novel approach, utilizing modified Chebyshev functions, demonstrates significant potential in reducing phase distortions within 5G technology applications. Unlike traditional Chebyshev functions, this method incorporates strategically placed transmission zeros— complex conjugate pairs on the s-variable complex plane—without increasing the filter circuit's order. This innovation results in a low-order filter circuit characterized by uniform phase response and group delay characteristics (GDT), offering an effective solution for matching circuit design with less phase-frequency distortion and improved group delay uniformity across diverse load conditions. The modified Chebyshev approximation outperforms its classical counterpart in both phase linearity and selectivity within the 1 to 1.2 cutoff frequency range. This enhancement is crucial for the development of low-frequency filters, with broader implications for creating high-frequency, band-pass, and band-stop filters via known frequency transformations. Empirical results validate the proposed method's reliability and effectiveness, marking a significant advancement in the field of radio engineering by addressing broadband matching challenges with increased efficiency and simplified design implementations.

2024-01-01T00:00:00Z Amangeldy, Nurzada Gazizova, Nazerke Milosz, Marek Kurmetbek, Bekbolat Nazyrova, Aizhan Kassymova, Akmaral http://repository.enu.kz/handle/enu/30648 2026-03-25T19:03:26Z 2025-01-01T00:00:00Z

Unsupervised Clustering and Ensemble Learning for Classifying Lip Articulation in Fingerspelling Amangeldy, Nurzada; Gazizova, Nazerke; Milosz, Marek; Kurmetbek, Bekbolat; Nazyrova, Aizhan; Kassymova, Akmaral This paper presents a new methodology for analyzing lip articulation during fingerspelling aimed at extracting robust visual patterns that can overcome the inherent ambiguity and variability of lip shape. The proposed approach is based on unsupervised clustering of lip movement trajectories to identify consistent articulatory patterns across different time profiles. The methodology is not limited to using a single model. Still, it includes the exploration of varying cluster configurations and an assessment of their robustness, as well as a detailed analysis of the correspondence between individual alphabet letters and specific clusters. In contrast to direct classification based on raw visual features, this approach pre-tests clustered representations using a model-based assessment of their discriminative potential. This structured approach enhances the interpretability and robustness of the extracted features, highlighting the importance of lip dynamics as an auxiliary modality in multimodal sign language recognition. The obtained results demonstrate that trajectory clustering can serve as a practical method for generating features, providing more accurate and context-sensitive gesture interpretation.

2025-01-01T00:00:00Z Zhukabayeva, Tamara Zholshiyeva, Lazzat Ven-Tsen, Khu Mardenov, Yerik Adamova, Aigul Karabayev, Nurdaulet Abdildayeva, Assel Baumuratova, Dilaram http://repository.enu.kz/handle/enu/30647 2026-03-25T19:03:31Z 2024-01-01T00:00:00Z

Towards robust security in WSN: a comprehensive analytical review and future research directions Zhukabayeva, Tamara; Zholshiyeva, Lazzat; Ven-Tsen, Khu; Mardenov, Yerik; Adamova, Aigul; Karabayev, Nurdaulet; Abdildayeva, Assel; Baumuratova, Dilaram One of the most important aspects of the effective functioning of wireless sensor network (WSN) is their security. Despite significant progress in WSN security, there are still several unresolved issues. Many review studies have been published on the problems of possible attacks on WSN and their identification. However, due to the lack of their systematic analysis, it is not possible to fully substantiate practical recommendations for the effective application of the proposed solutions in the field of WSN security. In particular, the creation of methods that provide a high degree of security while minimizing computational effort and costs, and the development of effective methods for detecting and preventing attacks on WSN. The purpose of this document is to fill this gap. The article presents the results of the study in the form of a systematic analysis of the literature with a targeted selection of sources to identify the most effective methods for detecting and preventing attacks on WSN. By identifying the security of WSN, which has not yet been addressed in research works, the review aims to reduce its impact. As a result, our extended taxonomy is presented, including attack types, datasets, effective WSN attack detection methods, countermeasures, and intrusion detection systems (IDS).

2024-01-01T00:00:00Z Begimbetova, Dinara Burska, Agata N. Baltabekova, Aidana Kussainova, Assiya Kukanova, Assiya Fazyl, Fatima Ibragimova, Milana Manekenova, Kenzhekyz Makishev, Abay Bersimbaev, Rakhmetkazhi I. Sarbassov, Dos D. http://repository.enu.kz/handle/enu/30646 2026-03-25T19:01:09Z 2024-01-01T00:00:00Z

The Vitamin C Enantiomers Possess a Comparable Potency in the Induction of Oxidative Stress in Cancer Cells but Differ in Their Toxicity Begimbetova, Dinara; Burska, Agata N.; Baltabekova, Aidana; Kussainova, Assiya; Kukanova, Assiya; Fazyl, Fatima; Ibragimova, Milana; Manekenova, Kenzhekyz; Makishev, Abay; Bersimbaev, Rakhmetkazhi I.; Sarbassov, Dos D. The use of vitamin C (VC) in high doses demonstrates a potent tumor suppressive effect by mediating a glucose-dependent oxidative stress in Kirsten rat sarcoma (KRAS) mutant cancer cells. VC with arsenic trioxide (ATO) is a promising drug combination that might lead to the development of effective cancer therapeutics. Considering that a tumor suppressive effect of VC requires its highdose administration, it is of interest to examine the toxicity of two enantiomers of VC (enantiomer d-optical isomer D-VC and natural l-optical isomer L-VC) in vitro and in vivo. We show that the combinations of L-VC with ATO and D-VC with ATO induced a similar cytotoxic oxidative stress in KrasG12D-expressing mutant cancer cells as indicated by a substantial increase in reactive oxidative species (ROS) production and depolarization of mitochondria. To examine the L-VC and D-VC toxicity effects, we administered high doses of D-VC and L-VC to CD1 mice and carried out an evaluation of their toxic effects. The daily injections of L-VC at a dose of 9.2 g/kg for 18 days were lethal to mice, while 80% of mice remained alive following the similar high-dose administration of D-VC. Following the drug injection courses and histopathological studies, we determined that a natural form of VC (L-VC) is more harmful and toxic to mice when compared to the effects caused by the similar doses of D-VC. Thus, our study indicates that the two enantiomers of VC have a similar potency in the induction of oxidative stress in cancer cells, but D-VC has a distinctive lower toxicity in mice compared to L-VC. While the mechanism of a distinctive toxicity between D-VC and L-VC is yet to be defined, our finding marks D-VC as a more preferable option compared to its natural enantiomer L-VC in clinical settings.

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