Stability Region Research Articles

RUSSIA’S HYBRID WARFARE IN THE WESTERN BALKANS: GEOPOLITICAL STRATEGIES AND PROXY ACTORS

This paper examines Russia’s hybrid warfare tactics against the Western Balkans, focusing on using direct and indirect methods to exert influence in the region. The study delves into Russia’s strategic use of media manipulation, cyberattacks, and disinformation campaigns, alongside its employment of proxy state and non-state actors such as Serbia, Republika Srpska, and the Serbian Orthodox Church. Leveraging historical, cultural, and religious ties, Russia seeks to destabilize the Western Balkans and prevent closer integration with NATO and the European Union. Special attention is given to the geopolitics of elections, where Russia manipulates electoral processes in countries like Montenegro and North Macedonia to favour pro-Russian or anti-Western political forces. By analyzing key case studies, this paper explores how Russian hybrid warfare exploits regional vulnerabilities—such as ethnic divisions and weak political institutions—while employing tactics of soft power and military cooperation. The findings indicate that Russia’s hybrid warfare, including electoral manipulation, poses a significant threat to regional stability and international security, underscoring the need for strengthened Western engagement to counter Russian influence. This study offers critical insights into the evolving nature of hybrid warfare and its implications for the geopolitical landscape of Southeast Europe.

Evaluation of the influence of freeze–thaw cycles on the joint strength of granite in the Eastern Tibetan Plateau, China

The freeze–thaw cycles will lead to rock deterioration and pose a significant threat to engineering stability in cold regions. In this study, granite samples collected from the Luanshibao Landslide in the Eastern Tibetan Plateau were subjected to a maximum of 120 freeze–thaw cycles at two temperature paths (− 10–20 °C and − 20–20 °C). The Brazilian test, uniaxial and triaxial compression tests were carried out to evaluate the strength behavior of samples while the scanning electron microscopy tests to investigate microstructural changes. The correlation between strength be-havior and microstructural evolution of samples after freeze–thaw cycles was discussed. Results indicate that the uniaxial compressive strength, elastic modulus, tensile strength, and peak strength of samples decreased nonlinearly with freeze–thaw cycles. Besides, freeze–thaw cycles exhibit more pronounced effect on the strength of samples, compared to the temperature path. Based on the Mohr–Coulomb criterion, a joint strength expression was proposed for the tensile, compressive, and shear strengths of granite, which characterizes the influence of freeze–thaw cycles and strength paths on strength behavior of granite samples. SEM images revealed the freeze–thaw damage to the microstructure of granite and further the deterioration of the mechanical properties. The results of this study can provide a valuable reference for assessing the freeze–thaw strength of granite in the context of construction in highland areas, guiding the development of more resilient engineering practices and informing future research on the long-term durability of materials in extreme climates.

The Dragon's Overwatch: Chinese Private Security Expansion in Latin America and the Caribbean

This scholarly disquisition furnishes a comprehensive exploration of the burgeoning presence of Chinese private security companies (PSCs) across Latin America and the Caribbean (LAC), delving into the strategic repercussions for regional security architectures and national sovereignty imperatives. Employing a meticulous qualitative methodology encompassing a thorough literature review, policy document analysis, and an examination of Chinese-language sources, the research elucidates the salient drivers catalyzing this phenomenon. These precipitating factors span cultural affinities, economic motivations, geopolitical ambitions, and the exigent security challenges besetting Chinese commercial entities operating within the LAC region. The operational modes of Chinese PSCs are subjected to forensic scrutiny, illuminating their diverse service offerings, geographical permeation across the region, and the obstacles they confront. Furthermore, the inquiry contextualizes the issue within the broader geopolitical milieu, accentuating concerns regarding transparency lacunae, regulatory deficiencies, and potential avenues for Chinese intelligence and military machinations, thereby potentially destabilizing the regional equilibrium. Ultimately, the research culminates in a series of substantive policy prescriptions aimed at mitigating risks, fortifying regional stability, and safeguarding national sovereignty through capacity-building initiatives, constructive engagement with Beijing, enhanced transparency mechanisms, and robust regional cooperation frameworks.

Peran Indonesia dalam Mewujudkan Stabilitas Keamanan Kawasan Regional Asean di Tengah Perebutan Pengaruh Negara-Negara Great Power

Geopolitical developments in Southeast Asia have become the center of attention of major world powers, especially the United States and China. ASEAN, through the ADMM and ADMM-Plus forums, plays an important role in maintaining regional security stability. This study aims to analyze Indonesia's role in realizing security stability in the ASEAN region in the midst of great power competition. The research methods used are qualitative with in-depth interviews, case studies, and secondary data analysis from various sources, including policy reports and official government statements. The results of the study show that Indonesia plays a role as a diplomatic mediator, a reinforcer of regional cooperation, and a defender of ASEAN sovereignty. ADMM-Plus also faces challenges in expanding membership, which requires careful geopolitical considerations. In conclusion, Indonesia has a crucial role in maintaining regional stability through multilateral cooperation and conflict resolution efforts in ASEAN.

Driven-dissipative phases and dynamics in non-Markovian nonlinear photonics

Interactions between photons (nonlinearities) enable a powerful form of control over the state of light. This control has enabled technologies such as light sources at new wavelengths, ultra-short optical pulses, frequency-comb metrology systems, even quantum light sources. Common to a wide variety of nonlinear optical technologies is an equilibrium between an energy source, such as an external laser, and dissipation, such as radiation loss or absorption. In the vast majority of these systems, the coupling between the system and the outside world (which leads to loss) is well described as “Markovian,” meaning that the outside world has no memory of its past state. In this work, we introduce a class of driven-dissipative systems in which a nonlinear cavity experiences non-Markovian coupling to the outside world. In the classical regime, we show that these non-Markovian cavities can have extremely low thresholds for nonlinear effects, as well as self-pulsing instabilities at THz rates, and rich phase diagrams with alternating regions of stability and instability. In the quantum regime, we show how these systems, when implemented on state-of-the-art platforms, can enable generation of strongly squeezed cavity states with intensity fluctuations that can be more than 15 dB below the classical limit, in contrast to the Markovian driven-dissipative cavity, in which the limit is 3 dB. In the regime of few-photon nonlinearity, such non-Markovian cavities can enable a deterministic protocol to generate Fock states of high order, which are long-desired, but still elusive at optical frequencies. We expect that exploiting non-Markovian couplings in nonlinear optics should in the future lead to even richer possibilities than those discussed here for both classical and quantum light manipulations.

Analysis of the Effectiveness of Connectivity Infrastructure Spending in the Bangka Belitung Islands Province

The purpose of this study is to analyze the correlation between APBN and APBD expenditures on the achievement of connectivity indicators. Secondary data sources were obtained from the Directorate of Budget Implementation, the Sintesa application, the OMSPAN and OMSPAN TKD applications, the Ministry of PUPR, and the BPS of the Bangka Belitung Islands Province. Data analysis uses the Pearson correlation method and qualitative descriptive. The results of the study indicate that APBN expenditure is negatively and very strongly correlated with the length of national roads. In addition, APBN expenditure is positively and very weakly correlated with the length of national roads in stable condition and has a moderate positive correlation with the percentage of national road stability. APBD expenditure is very weakly correlated with the length of provincial roads and is moderately correlated with the length of provincial roads in stable conditions and the percentage of stability. Regency/City APBD expenditure also has a very weak correlation and is negatively directed to the total length of district/city roads in the Bangka Belitung Islands Province and has a moderate correlation with the length of district/city roads in stable condition and the percentage of stability. APBN expenditure has a positive and very strong correlation with the length of regional roads and is positively and strongly correlated with the length of regional roads in stable conditions. APBN spending also has a moderate correlation with the percentage of regional road stability. Based on the relationship analysis using Pearson correlation, it was found that the total length of the road has a strong correlation and has a positive relationship with the ADHK GRDP. The Bangka Belitung Islands Province has a higher road stability than the national road stability and road stability in the Sumatra Region.

Land Subsidence Detection Using SBAS- and Stacking-InSAR with Zonal Statistics and Topographic Correlations in Lakhra Coal Mines, Pakistan

The adverse combination of excessive mining practices and the resulting land subsidence is a significant obstacle to the sustainable growth and stability of regions associated with mining activities. The Lakhra coal mines, which contain some of Pakistan’s largest coal deposits, have been overlooked in land subsidence monitoring, indicating a considerable oversight in the region. Subsidence in mining areas can be spotted early when using Interferometric Synthetic Aperture Radar (InSAR), which can precisely monitor ground changes over time. This study is the first to employ the Small Baseline Subset (SBAS)-InSAR and stacking-InSAR techniques to identify land subsidence at the Lakhra coal mines. This research offers critical insights into subsidence mechanisms in the study area, which has never been previously investigated for ground deformation monitoring, by utilizing 150 Sentinel-1A (ascending) images obtained between January 2018 and September 2023. A total of 102 deformation spots were identified using SBAS-InSAR, while stacking-InSAR detected 73 deformation locations. The most extensive cumulative subsidence in the Lakhra coal mine was −114 mm, according to SBAS-InSAR, with a standard deviation of 6.63 mm. In comparison, a subsidence rate of −19 mm/year was reported using stacking-InSAR with a standard deviation of 1.17 mm/year. The rangeland covered 88.8% of the total area and exhibited the most significant deformation values, as determined by stacking and SBAS-InSAR techniques. Linear regression showed that there was not a strong correlation between subsidence and topographic factors. As detected by optical remote sensing data, the subsidence locations were near or above the mines in the research area, indicating that widespread mining in Lakhra coal mines was the cause of subsidence. Our findings suggest that SAR interferometric time series analysis is helpful for proactively identifying and controlling subsidence difficulties in mining regions by closely monitoring activities, hence reducing negative consequences on operations and the environment.

RUSSIA’S HYBRID WARFARE IN THE WESTERN BALKANS: GEOPOLITICAL STRATEGIES AND PROXY ACTORS

This paper examines Russia’s hybrid warfare tactics against the Western Balkans, focusing on using direct and indirect methods to exert influence in the region. The study delves into Russia’s strategic use of media manipulation, cyberattacks, and disinformation campaigns, alongside its employment of proxy state and non-state actors such as Serbia, Republika Srpska, and the Serbian Orthodox Church. Leveraging historical, cultural, and religious ties, Russia seeks to destabilize the Western Balkans and prevent closer integration with NATO and the European Union. Special attention is given to the geopolitics of elections, where Russia manipulates electoral processes in countries like Montenegro and North Macedonia to favour pro-Russian or anti-Western political forces. By analyzing key case studies, this paper explores how Russian hybrid warfare exploits regional vulnerabilities—such as ethnic divisions and weak political institutions—while employing tactics of soft power and military cooperation. The findings indicate that Russia’s hybrid warfare, including electoral manipulation, poses a significant threat to regional stability and international security, underscoring the need for strengthened Western engagement to counter Russian influence. This study offers critical insights into the evolving nature of hybrid warfare and its implications for the geopolitical landscape of Southeast Europe.

Unmanned surface vehicles for naval warfare and maritime security

There is a growing need to implement maritime defensive systems, covering both medium-range and close-in defenses. This is in response to the escalating threat posed by unmanned surface vehicles (USVs) in a rapidly changing environment. As unmanned technologies become more widespread and advanced, the proactive deployment of these defensive measures is becoming imperative. This strategic approach aims to reduce risks, protect vital assets, and bolster the Navy’s flexibility in adapting to the evolving dynamics of contemporary naval warfare. This initiative aligns with broader goals of upholding maritime security and contributing to regional stability amid rapidly shifting conditions in warfare. This perspective covers the relevant aspects of USV development, and the countermeasures being considered.

Yield, varietal zoning of spring barley in Tyumen region and assessment of ecological plasticity and stability of its varieties

The purpose of the study is to assess the yield of spring barley in the production and state variety testing of the Tyumen region for 2017-2022, its varietal zoning, as well as the yield and adaptability of varieties for 2021-2023 in the conditions of the subtaiga. There was a significant excess of yield in state variety testing compared to production, which averaged 15.0 c/ha in 2017-2022. The originators of most of the varieties approved for use are the Federal Research Centers of the Urals and Western Siberia. The variety Kudesnik (44.8 c/ha) was the best in terms of average yield, and Chelyabinsky 99 (69.2%) – in terms of the realization of its potential. Stress resistance is low in all varieties, which ranged from -31.2 (Orda) to -49.0 (Nord 18/2613). All varieties had significant yield variability, ranging from 42.7% (Orda) to 69.4% (Nord 18/2613). Strong responsiveness to changes in conditions was detected in the varieties KVS Jessy (bi = 1.10) and Nord 18/2613 (bi = 1.34), which are classified as intensive. The varieties Acha, Despina, Kudesnik, Divny and Abba, with a regression coefficient equal to or close to one, were characterized as plastic, and the varieties Orda, Chelyabinsky 99 and Abalak were poorly responsive to changes in conditions (bi < 1). Yield stability is low in all varieties, from St2 = 0.52 (Nord 18/2613) to St2 = 0.82 (Abalak, Orda). The variety Kudesnik (Ei..=4.8) was characterized the greatest indicator of the genotypic effect, and the variety Abalak (143.5%) – the indicator of the yield and stability of the variety. The varieties Abalak (sum of ranks 32) and Kudesnik (sum of ranks 35) were recognized as the best by the sum of the ranks of the indicators of yield and adaptability of spring barley for 2021-2023 in the subtype of the Tyumen region.

A class of explicit second derivative general linear methods for non-stiff ODEs

In this paper, we construct explicit second derivative general linear methods (SGLMs) with quadratic stability and a large region of absolute stability for the numerical solution of non-stiff ODEs. The methods are constructed in two different cases: SGLMs with p = q = r = s and SGLMs with p = q and r = s = 2 in which p, q, r and s are respectively the order, stage order, the number of external stages and the number of internal stages. Examples of the methods up to order five are given. The efficiency of the constructed methods is illustrated by applying them to some well-known non-stiff problems and comparing the obtained results with those of general linear methods of the same order and stage order.

Numerical evaluation of ground source heat pumps in a thawing permafrost region

Permafrost degradation poses significant environmental and geological challenges in Arctic and subarctic regions, particularly in areas like Umiujaq, Canada. The warming climate leads to thawing permafrost, causing ground instability, disrupting hydrology, and impacting local built environment. This study evaluates the use of Ground Source Heat Pump (GSHP) operation for mitigating ground subsidence in a permafrost region using a two-dimensional Thermo-Hydro-Mechanical (THM) coupled finite element analysis considering the ground poro-elastic and poro-plastic responses. The research uses a single-well scenario to demonstrate the interactions among thermal, hydraulic, and mechanical processes. The impact of GSHP operation under different temperature management strategies, including a scenario with a constant GSHP temperature of −5 °C throughout the year is numerically investigated. Results indicate that GSHP operation exacerbates ground deformation near the borehole, particularly during winter months. However, maintaining GSHP operation throughout the entire year can mitigate extreme subsidence fluctuations, leading to a more stable subsurface environment. While GSHP systems provide effective thermal regulation, their operation can introduce mechanical stresses that potentially disturb the ground close to the borehole. Therefore, careful design, operation, and further research are essential to balance thermal benefits with ground stability in permafrost regions.

Demonstration of high-frequency self-pulsing oscillations in an active silicon micro-ring cavity

We experimentally investigated the self-pulsing (SP) oscillations induced by the thermo-optic, free carrier, and Kerr nonlinear effects in integrated active silicon microring resonators. We demonstrate high frequency self-pulsing oscillations (up to 30 MHz) by applying a few millivolts of reverse bias voltage to the PIN junction of the active cavity. We illustrate that the shape of those oscillations (i.e., frequency and duty cycle) can be controlled by adjusting the CW input power and applying a reverse bias voltage to the PIN junction for carrier removal. This controlling is important for synchronizing the cavity which is crucial for neural network applications. Furthermore, we utilize a mathematical model for visualizing the stability regions by numerically studying coupled mode theory in silicon microcavity under different conditions.

Dynamical state and driving region of combustion instability in a turbulent combustor with a variable swirling flow system

We experimentally study the dynamical state and driving region of combustion instability in a turbulent combustor under low- and high-swirling flow conditions by the complex-systems approach. As the swirl number is increased, the combustion state undergoes a transition from stable combustion to complex combustion instability with large-amplitude modulations via low- and high-amplitude combustion instability. A chaotic state emerges during combustion instability with large-amplitude modulations. A symbolic dynamics-based thermoacoustic power network can identify the emergence of the thermoacoustic power source during combustion instability. The driving region of combustion instability can be clearly extracted from the symbolic dynamics-based synchronization index and the local node entropy in the Rayleigh index-based transition network. Reservoir computing has a potential use in clarifying the phase synchronized state between acoustic pressure and heat release rate fluctuations during the chaotic state in combustion instability with large-amplitude modulations.

PRISTINA: GLOBAL EXPERTS DISCUSS THE IMPACT OF RUSSIAN AGGRESSION ON THE STABILITY OF EUROPE AND THE BALKANS

The report titled “Global Experts Discuss the Impact of Russian Aggression on the Stability of Europe and the Balkans” provides a comprehensive overview of discussions held during an international conference organized by the Institute for Hybrid Warfare Studies “OCTOPUS” in Pristina. The conference gathered prominent experts, diplomats, and scholars to address the wide-ranging geopolitical impacts of Russia's war in Ukraine on both Europe and the Balkans. Key speakers highlighted the evolving threats posed by Russian aggression. Glauk Konjufca underscored the dangerous parallels between Russia’s “Russian world” doctrine and Serbia’s expansionist “Serbian world” ambitions in the Balkans. Dr. Jennifer Cassidy warned of the risk of Serbian military intervention in Kosovo, echoing Russia's tactics in Ukraine. Jason Jay Smart detailed Russia’s global destabilization strategy, including its use of proxy wars and criminal alliances to divert attention from Ukraine. Discussions on hybrid warfare featured Dr. Pekka Kallioniemi, who analyzed Russia’s use of disinformation campaigns and social media manipulation to influence global public opinion and destabilize democracies. Ihor Todorov and Pandeli Majko focused on the rise of nationalism and regional instability, stressing the need for unified European and NATO responses to these growing threats. The report captures the key points of the event, emphasizing the importance of countering Russian influence and strengthening democratic institutions in Europe and the Balkans to preserve stability and security in the face of ongoing aggression.

Operational Modal Analysis of Self-excited Vibrations in Milling Considering Periodic Dynamics

Abstract A new method is presented to identify the dynamics of regenerative chatter from measured process vibrations in milling. This method combines the synchronous once-per-revolution sampling of process vibrations with Operational Modal Analysis to estimate the Floquet multipliers of the delayed linear time-periodic dynamics in milling, all from the natural process vibrations without external excitation. The identified multipliers quantify vibration stability, enabling chatter prediction before it occurs. In addition to this, they can be used to calibrate physics-based chatter models based on vibration measurements solely within the stable region. The method's accuracy in identifying Floquet multipliers is validated through extensive numerical simulations and two experimental case studies. The results show that chatter due to both Hopf and period-doubling bifurcations can be predicted from the process vibrations during stable cuts. Moreover, the experimental case studies demonstrate a vibration measurement system for implementing the presented method in standard milling operations and confirm its effectiveness in practice.

Estimates of (convective core) masses, radii, and relative ages for ~14,000 Gaia-discovered gravity-mode pulsators monitored by TESS

Gravito-inertial asteroseismology saw its birth from the 4-year-long light curves of rotating main-sequence stars assembled by the Kepler\/ space telescope. High-precision measurements of internal rotation and mixing are available for about 600 stars of intermediate mass so far that are used to challenge the state-of-the-art stellar structure and evolution models. Our aim is to prepare for future large ensemble modelling of gravity-mode pulsators by relying on a new sample of such stars recently discovered from the third Data Release of the Gaia\/ space mission and confirmed by space photometry from the TESS mission. This sample of potential asteroseismic targets is about 23 times larger than the Kepler\/ sample. We use the effective temperature and luminosity inferred from Gaia\/ to deduce evolutionary masses, convective core masses, radii, and ages for sim 14,000 gravity-mode pulsators classified as such from their nominal TESS light curves. We do so by constructing two dedicated grids of evolutionary models for rotating stars with input physics from the asteroseismic calibrations of Kepler\/ pulsators. These two grids consider the distribution of initial rotation velocities at the zero-age main sequence deduced from gravito-inertial asteroseismology, for two extreme values found for the metallicity of stars deduced from spectroscopy M/H = 0.0$ and $-0.5$). We find the new gravity-mode pulsators to cover an extended observational instability region covering masses from about 1.3 to about 9 We provide their mass-luminosity and mass-radius relations, as well as convective core masses. Our results suggest that oscillations excited by the opacity mechanism occur uninterruptedly for the mass range above about 2 where stars have a radiative envelope aside from thin convection zones in their excitation layers. Our evolutionary parameters for the sample of Gaia\/ -discovered gravity-mode pulsators with confirmed modes by TESS offer a fruitful starting point for future TESS ensemble asteroseismology once a sufficient number of modes is identified in terms of the geometrical wave numbers and overtone for each of the pulsators.

Research on the potential of integrated vehicle control with closed-loop phase portrait analysis

The phase portrait is an important tool for analyzing vehicle stable region widely utilized in vehicle dynamic control systems. At handling limits, traditional open-loop vehicle stable region constraints will restrict the vehicle control ability, while the closed-loop actuator interventions can help states outside the open-loop stable region converge back to stable origin, which is more suitable for constraining vehicle states under extreme working conditions. This article systematically analyzes the potential of integrated vehicle control with closed-loop phase portrait. Firstly, a vehicle dynamic model considering actuator dynamics and tire transient characteristics is established. Then, a numerical optimal control method for calculating closed-loop controllability region is introduced. The controllability region under different friction coefficients, vehicle speeds, convergence time, vehicle steering response characteristics, actuator time constants, and tire transient characteristics are discussed and analyzed. In terms of different control inputs combinations, this article displays the controllability regions under different front steering angles, rear steering angles, direct yaw moments, and their synergistic performances. Control input laws derived from numerical optimization are summarized in two specific directions. Finally, a comparative analysis of open-loop stable regions and closed-loop controllability regions confirms the superiority of the proposed method. Potential applications of the systematic analysis are also discussed.

Spatiotemporal fluctuation induces Turing pattern formation in the chemical Brusselator

Chemical reactions are embedded in spatiotemporal fluctuations instead of a constant environment. Here, we aimed to assess reaction–diffusion (RD) with dichotomous noise‐controlling system parameters in the Brusselator and examine the effect of these fluctuations on the dynamic behavior of chemical reactions. By performing a multiscale perturbation analysis, we demonstrated that the correlated noise can broaden the Turing region even if molecular memory (autocorrelation time) exists. However, for small noise, short‐term memory promotes Turing instability. The instability of the Brusselator is determined by the noise strength, which belongs to the optimal region if the diffusion coefficient is fixed. Turing pattern selection and stability are also governed by the dynamic character of the amplitude equation, and the entire Turing instability region shifts to the right in the phase space with noise perturbation. Finally, numerical simulations validate the theoretical derivation that correlated noise can amplify Turing pattern formation to maintain distinct patterns.

Prediction and Analysis of Surface Residual Deformation Considering the Impact of Groundwater in Mines

With economic development and coal resource exploitation, the area of mined-out zones is expanding continuously. The traditional waste disposal methods no longer meet the current demands, making it urgent to evaluate and reuse the surface stability of these mined-out zones. Surface residual deformation is a process where voids and fissures within the mined-out zones are gradually filled and compacted, affecting the overlying rock structure. Additionally, groundwater significantly impacts the strength of the overlying rock, leading to increased subsidence. Therefore, predicting surface residual deformation while considering the effects of groundwater is crucial for forecasting surface deformation and assessing stability in mined-out zones. This study, taking into account the characteristics of subsidence zones and the impact of groundwater on the compaction of fractured rock masses, uses equivalent mining height and probability integral methods to develop a predictive model for surface residual deformation incorporating groundwater effects. Predictions for the study area show that groundwater exacerbates surface residual deformation, with various deformation values ranging from 33.8% to 51.9%. The surface stability categories are divided into stable and essentially stable regions based on the residual deformation’s impact on the working face. This model fully considers the influence of groundwater on residual deformation in mined-out zones, refining existing mining subsidence theories, addressing deformation issues caused by adverse groundwater factors, and providing a theoretical basis for predicting residual deformation and evaluating stability in mined-out zones, promoting the sustainable development of land and environmental resources in mining areas.