The Legitimacy of Russia’s Actions in Ukraine

In this post for LSE International History, Björn Alexander Düben analyses the recent outbreak of conflict in Ukraine. In the article, Dr Düben examines Russia’s military campaign in Ukraine and its annexation of Ukrainian territory. Dr Düben argues that Russia’s claims to parts of Ukraine and its annexation of territory in the country has little basis in history and the parameters of international law

Banking on Beijing: what the Ukraine crisis means for the future of China-Russia relations

The crisis in Ukraine has propelled China-Russia relations to new heights. Against the backdrop of the events in Eastern Europe, Beijing and Moscow have been able to initiate a number of bilateral economic, financial and energy projects that have promised an unprecedented degree of integration between the two countries. Most of these plans are unlikely to be fully implemented, but Russia’s novel isolation has provided the impulse to open up various sectors of the Russian economy that were previously off limits to the Chinese. Moscow’s move to seek much closer integration with Beijing derives from tactical considerations, rather than a coherent long-term strategy, and Russia’s growing isolation from the West will likely render it continuously more dependent on China. Beijing’s official reaction to the turmoil in Ukraine has been reticent and equivocal, but the major state-controlled Chinese media have been outspokenly supportive of Russia’s claims. The apparent ambivalence in China’s reaction to the Ukraine crisis reflects its concerns about the most problematic aspect of Moscow’s actions there – the blatant infringement of Ukraine’s sovereignty and the annexation of a part of its territory. But Beijing’s irritation about Russia’s blatant violations of the principles of sovereignty and non-interference was largely offset by its even more profound opposition to the pro-Western regime change in Kiev. Russia’s actions in Ukraine have also resonated with nationalist factions in Beijing who have long argued for a greater assertiveness in advancing China’s own territorial claims vis-à-vis its neighbours

Revising history and ‘gathering the Russian lands’: Vladimir Putin and Ukrainian nationhood

While the causes of Russia’s war against Ukraine are often discussed in terms of geopolitics, another factor that seems to have been an important part of Vladimir Putin’s rationale for launching the invasion in February 2022 is his nationalist vision of Ukraine – or significant portions of it – as a historic part of Russia. In the years leading up to the invasion, Putin wrote and spoke at great length about Ukrainian history, establishing a narrative centred around the denial of Ukraine’s historic state- and nationhood, presenting Ukrainians and Russians as a single people, and laying claim to large swathes of Ukrainian territory as ‘primordial’ Russian lands. While analysts have long struggled to adequately assess it, Putin has used this narrative to justify the invasion of Ukraine to a domestic audience, and it appears to have influenced the Kremlin’s war aims and the conduct of Russian troops on the ground. There is much to suggest that Putin’s invocation of such nationalist and irredentist themes, rather than being a purely tactical move, reflects his genuine convictions. In addition to analysing how and why Putin has been (mis)interpreting Ukrainian history and denying Ukrainian nationhood, this article examines how this narrative has affected the Russian war effort and how far Putin’s territorial claims in Ukraine extend

The long shadow of the Soviet Union: demystifying Putin's rhetoric towards Ukraine

As tensions between Russia and Ukraine reach an almost-tipping point, Björn Alexander Düben analyses the historical and geopolitical rhetoric Putin and his government have deployed against the post-Maidan Ukraine since 2014. Asking, can this be seen as another Russian assertion of dominance in the post-Soviet region, could there be reasons closer to home, or why tensions across the border seem to once again be at a breaking point? From global oil prices to regime consolidation, an analysis into the words of Russia’s elites could unveil what future Europe is steering towards

Exploiting the chaotic behaviour of atmospheric models with reconfigurable architectures

Reconfigurable architectures are becoming mainstream: Amazon, Microsoft and IBM are supporting such architectures in their data centres. The computationally intensive nature of atmospheric modelling is an attractive target for hardware acceleration using reconfigurable computing. Performance of hardware designs can be improved through the use of reduced-precision arithmetic, but maintaining appropriate accuracy is essential. We explore reduced-precision optimisation for simulating chaotic systems, targeting atmospheric modelling, in which even minor changes in arithmetic behaviour will cause simulations to diverge quickly. The possibility of equally valid simulations having differing outcomes means that standard techniques for comparing numerical accuracy are inappropriate. We use the Hellinger distance to compare statistical behaviour between reduced-precision CPU implementations to guide reconfigurable designs of a chaotic system, then analyse accuracy, performance and power efficiency of the resulting implementations. Our results show that with only a limited loss in accuracy corresponding to less than 10% uncertainty in input parameters, the throughput and energy efficiency of a single-precision chaotic system implemented on a Xilinx Virtex-6 SX475T Field Programmable Gate Array (FPGA) can be more than doubled

Validating optimisations for chaotic simulations

It is non-trivial to optimise computations of chaotic systems since slightly perturbed simulations diverge exponentially over time due to the well-known butterfly effect if bit-reproducible results are not achieved. Therefore, two model setups that show the same quality in the representation of a chaotic system will show uncorrelated behaviour if integrated long enough, hence it is challenging to check whether a given optimisation degrades model quality. Most models in computational fluid dynamics show chaotic behaviour. In this paper we focus on models of atmosphere and ocean that are vital for predictions of future weather and climate. Since forecast quality is usually limited by the available computational power, optimisation is highly desirable. We describe a new method for accepting or rejecting an optimised implementation of a reconfigurable design to simulate dynamics of a chaotic system. We apply this method to optimise numerical precision to a minimal level of stencil computations that can be used in an idealised ocean model, and show the performance improvements gained on an FPGA. The proposed method enables precision reduction for the FPGA so that it computes up to 9 times faster with 6 times lower energy consumption than an implementation on the same device with double precision arithmetic, while ensuring the optimised design to have acceptable numerical behaviour