State Research Center of the Russian Federation

The purpose of the study: development and experimental validation of a methodology for adaptive cyber threat assessment in the telemetry infrastructure of railway transport using a digital twin for safe machine learning model retraining. Research methods: cyberattack scenario modeling, statistical analysis of time series, machine learning techniques, synthetic data generation within a digital twin environment. Results obtained: an architecture for an adaptive cyber threat detection system is proposed, implementing a closed-loop cycle of monitoring, evaluation, and safe model retraining within an isolated digital twin environment. A synthetic dataset was generated to simulate six types of stealthy and evolving cyberattacks targeting the telemetry of traction power systems and SCADA systems in railway infrastructure. Experimental results demonstrate that a static machine learning model suffers severe performance degradation under concept drift, exhibiting extremely low recall. In contrast, the proposed adaptation mechanism—based on the analysis of false negatives and the targeted addition of representative examples to the training set—significantly improves recall while maintaining high precision. Even the inclusion of a small number of new samples (less than 3 % of the original dataset) yields a substantial increase in F1-score, confirming the approach’s effectiveness under strict regulatory constraints that limit direct intervention in real critical infrastructure operations. Scientific novelty: The proposed approach is distinguished by the integration of a digital twin as a secure environment for generating synthetic attack scenarios and retraining the detection model based on false-negative analysis. This enables effective compensation for concept drift without disrupting the operation of the actual railway infrastructure. Contributions: Kotenko I. V. – development of the problem statement and general approach to adaptive assessment of cyber threats in the telemetry infrastructure of railway transport; Kotenko I. V., Saenko I. B. and Mityakov E. S. – analysis of modern research on cyber threat assessment and development of the architecture of the adaptive cyber threat assessment system; Mityakov E. S. – experimental study of the proposed approach; Kotenko I. V., Saenko I. B. and Mityakov E. S. – analysis of the research results.

The age and size of the maturity reproduction of pollock individuals are subject to significant interannual variability. The main spawning of pollock on the shelf was observed: in Unimaksky district – in the 2nd decade of March and the 2nd decade of April, above depths of 75–100 m; in Pribilovsky district – in the 3rd decade of April, above depths of 70–75 m; in Matveevsky district – in the 1st decade of May, above depths of 115–140 m. In Unimak district, the main concentrations of pollock during the peak of spawning spatially coincided with the main concentrations of egg. Such coincidences were observed irregularly in the Pribylovsky and Matveevsky districts. In March, the larvae that originated from winter spawning lived not only above significant depths – 600–2000 m, with a favorable temperature regime (3,1–4,5 C), but also in the shelf zone of the Unimaksky district, where the development conditions are more severe. The largest catches of larvae of the spring generation were observed in mid-May and early June. The larvae of the spring generation are confined to the spawning ground, which indicates the absence of drift. The main reason for the variability of stocks is the number of generations included in the fishable stock. From 1980 to 2024, there were 8 high abundance generations. The average annual pollock catch in the area over a 45-year period was 1,2 million tons. Pollock stocks in the eastern Bering Sea are highly stable. Periods of low stock levels are short-lived and last several years. The average long-term exploitation rate was 12,6%, which indicates a relatively low harvest level.

This paper presents an analysis of the salmon catch in 2024 in the Far Eastern Fisheries Basin, which is based on the state monitoring data of the number of Pacific salmon approaches and official fishery statistics provided by the Territorial departments of the Federal Fisheries Agency. The reasons for the deviation of actual salmon catches from forecast estimates are analyzed.

In 2023–2024, observations on the implementation of recreation fishery of the Baikal omul were carried out for the first time. The volume of catch, the intensity of recreation fishery of Baikal omul and the catch structure were determined. the annual volume of fishing is estimated at 110 tons, and in winter «catches from the ice» reached 82%. Аnalysis of the catch structure showed that the individuals of the coastal morphological and ecological group formed the basis of catches.

This article examines various aspects of the seaweed harvest – Saccharina japonica (Japanese kelp) – by Japanese fishermen within Russian territorial waters near the small, uninhabited Signalny Island in the Sovetsky Strait of the Pacific Ocean, part of the Lesser Kuril Islands. Signalny Island is part of the South Kuril District of the Sakhalin Region. The article focuses on conservation measures that enable the sustainable harvest of this seaweed in Russian waters to be maintained on a long-term basis under joint agreements.

The conceptual issues of the formal representation of the dynamic structure of the spawning migration of the Aradesque greenlinling Pleurogrammus azonus are considered. Based on the factual material and literature data, its functional character is being investigated. It is assumed that spawning migration is a natural continuation of the spring migration going ashore. Its fundamental difference is the formation of spawning schools with a layered age structure. They begin to form when producers move into the deep (subsurface) water mass. The appearance of mating coloration in old males is a stimulating signal for grouping other producers around them. Leadership in the spawning school initially belongs to the old males and then passes to the old females. When moving, producers of the older age groups adhere to more stable environmental conditions compared to producers of the younger age groups. The essence of the proposed strategy is the layered movement of producers with the leadership of the older age groups, after the emergence of the mating coloration in the latter.

Methods of modeling difficult-to-formalize objects are considered. The complexity of formalization is due to the manifestation of non-factors, which differ in the signs of manifestation when constructing models, and this is expressed in the weak predictability of the object’s behavior, a large number of influencing factors (often described qualitatively), and the difficulties of their quantitative measurement. As an example, the technological process of feed production is analyzed, and the process formalization is complicated by various types of non-factors (uncertainty, vagueness, etc.). The example of this object demonstrates the possibility of using a fuzzy-possibility approach in constructing models with uncertainty compensation.