Traditional Stability Theory Research Articles

India’s sea-based nuclear forces and strategic stability in South Asia

ABSTRACT Nuclear ballistic missile submarines (SSBNs) are traditionally believed to provide assured second-strike capability and stabilize deterrence. This paper contests this classical assumption in South Asia’s context and argues that SSBN capability to become secure and credible deterrent depends upon doctrinal issues, command and communication systems, and operational readiness of SSBN force. In a dyad, if both countries have invulnerable second strike capability, there is less incentive to strike first. Whereas invulnerability of one country incentivizes first strike. In South Asian strategic situation, an assured sea-based second-strike capability may contribute to India’s aggressive nuclear posture. This paper evaluates New Delhi’s induction of SSBNs in light of its stated notion of minimalism, as declared in its nuclear doctrine, and discusses in the context of traditional stability theory associated with the development of SSBN force. This paper primarily considers deterrence stability and crisis stability as two dependent variables to study how India’s sea-based nuclear capability affects strategic stability in South Asia.

Data-Driven Stability Assessment of Multilayer Long Short-Term Memory Networks

Recurrent Neural Networks (RNNs) are increasingly being used for model identification, forecasting and control. When identifying physical models with unknown mathematical knowledge of the system, Nonlinear AutoRegressive models with eXogenous inputs (NARX) or Nonlinear AutoRegressive Moving-Average models with eXogenous inputs (NARMAX) methods are typically used. In the context of data-driven control, machine learning algorithms are proven to have comparable performances to advanced control techniques, but lack the properties of the traditional stability theory. This paper illustrates a method to prove a posteriori the stability of a generic neural network, showing its application to the state-of-the-art RNN architecture. The presented method relies on identifying the poles associated with the network designed starting from the input/output data. Providing a framework to guarantee the stability of any neural network architecture combined with the generalisability properties and applicability to different fields can significantly broaden their use in dynamic systems modelling and control.

Did glacially induced TPW end the ice age? A reanalysis

Previous studies of Earth rotation perturbations due to ice-age loading have predicted a slow secular drift of the rotation axis relative to the surface geography (i.e. true polar wander, TPW) of order of several degrees over the Plio-Pleistocene. It has been argued that this drift and the change in the geographic distribution of solar insolation that it implies may have been responsible for important transitions in ice-age climate, including the termination of ice-age cycles.We use a revised rotational stability theory that incorporates a more accurate treatment of the Earth's background ellipticity to reconsider this issue, and demonstrate that the net displacement of the pole predicted in earlier studies disappears. This more muted polar motion is due to two factors: first, the revised theory no longer predicts the permanent shift in the rotation axis, or the so-called 'unidirectional TPW', that appears in the traditional stability theory; and, second, the increased background ellipticity incorporated in the revised predictions acts to reduce the normal mode amplitudes governing the motion of the pole. We conclude that ice-age-induced TPW was not responsible for the termination of the ice age. This does not preclude the possibility that TPW induced by mantle convective flow may have played a role in major Plio-Pleistocene climate transitions, including the onset of Northern Hemisphere glaciation.

Adapting to a changing environment: non-obvious thresholds in multi-scale systems.

Many natural and technological systems fail to adapt to changing external conditions and move to a different state if the conditions vary too fast. Such 'non-adiabatic' processes are ubiquitous, but little understood. We identify these processes with a new nonlinear phenomenon-an intricate threshold where a forced system fails to adiabatically follow a changing stable state. In systems with multiple time scales, we derive existence conditions that show such thresholds to be generic, but non-obvious, meaning they cannot be captured by traditional stability theory. Rather, the phenomenon can be analysed using concepts from modern singular perturbation theory: folded singularities and canard trajectories, including composite canards. Thus, non-obvious thresholds should explain the failure to adapt to a changing environment in a wide range of multi-scale systems including: tipping points in the climate system, regime shifts in ecosystems, excitability in nerve cells, adaptation failure in regulatory genes and adiabatic switching in technology.

Stability and General Logics

AbstractIn this paper we make an attempt to study classes of models by using general logics. We do not believe that Lww is always the best logic for analyzing a class of models. Let K be a class of models and L a logic. The main assumptions we make about K and C are that K has the L‐amalgamation property and, later in the paper, that K does not omit L‐types. We show that, if modified suitably, most of the results of stability theory hold in this context. The main difference is that existentially closed models of K play the role that arbitrary models play in traditional stability theory. We prove e. g. a structure theorem for the class of existentially closed models of K assuming that K is a trivial superstable class with ndop.

Enduring Misconceptions of Strategic Stability: The Role of Nuclear Missile-Carrying Submarines

This article exposes many of the flawed assumptions about the submarine leg of the nuclear triad implicit in traditional strategic stability theory. It argues that the US strategic studies literature has put too much emphasis on traditional stability theory and that stability, whether defined traditionally or in modern terms, is more threatened by submarine-based nuclear weapons than is generally realized. The article notes that, although the possibility of a major nuclear surprise attack is becoming increasingly remote, insofar as there currently exist military incentives to launch such attacks it is due in large part to submarine-launched ballistic missiles (SLBMs) which facilitate command and control decapitation strikes and threaten to negate options such as Launch on Warning. It moreover suggests that SLBMs are the strategic weapons most likely to endanger efforts to prevent loss of control in crises because: (1) US SLBMs do not contain Permissive Action Links (PALs); (2) in contrast to ICBMs, SLBMs regularrrl come into direct and potentially violent contact with enemy military forces in peacetime and are significantly more likely to come under direct attack in conventional war; and (3) SLBMs could make it particularly difficult for decision-makers to determine the source of a nuclear attack. The article concludes with several recommendations for enhancing strategic stability.