Towards Urban Air Mobility: NASAs Quadcopter Air Taxi Concept

Urban Air Mobility (UAM) is envisioned to be the future air transportation system over populated areas, where everything from small package delivery drones to passenger-carrying air taxis are able to interact safely and efficiently. The capacity of multi-rotor vehicles to perform vertical takeoff and landing (VTOL), together with their great maneuverability, make them an excellent choice for UAM aircraft. The accurate prediction of multirotor vehicles performance and acoustics is very challenging due to the unsteady and complex flows, as well as the aerodynamic interactions. By running high-fidelity computational fluid dynamics simulations on NASA supercomputers, researchers model the complex aerodynamics of multi-rotor flows, getting us closer to making UAM a reality

Predicting a Protein's Stability under a Million Mutations

Stabilizing proteins is a foundational step in protein engineering. However, the evolutionary pressure of all extant proteins makes identifying the scarce number of mutations that will improve thermodynamic stability challenging. Deep learning has recently emerged as a powerful tool for identifying promising mutations. Existing approaches, however, are computationally expensive, as the number of model inferences scales with the number of mutations queried. Our main contribution is a simple, parallel decoding algorithm. Our Mutate Everything is capable of predicting the effect of all single and double mutations in one forward pass. It is even versatile enough to predict higher-order mutations with minimal computational overhead. We build Mutate Everything on top of ESM2 and AlphaFold, neither of which were trained to predict thermodynamic stability. We trained on the Mega-Scale cDNA proteolysis dataset and achieved state-of-the-art performance on single and higher-order mutations on S669, ProTherm, and ProteinGym datasets. Code is available at https://github.com/jozhang97/MutateEverythingComment: NeurIPS 2023. Code available at https://github.com/jozhang97/MutateEverythin

Simulation of Influence of Transverse Wheel-Set Movement on Torsion Oscillations

With increasing importance of the railway transport the demands on economic and functional features of the railway traffic increase as well. The features are influenced by many factors, whose identification, direct measuring and impact detection are not easy to obtain in the real service. A computational simulation and a roller rig are suitable means, which enable to recognize an amount of physical limitation influences in conjunction with proposed vehicle construction and with supposed surrounding service conditions make everything clear before a vehicle commissioning. Therefore, the Simulink model, focused on the field of research of traction wheel-sets torsion dynamics and an influence of adhesion conditions, was built, has been used and developed within SGS (Student Grant Competition) and PhD study programs. In the past, the model served for investigation of torsion oscillation excited by changes in torque transfer. In this paper we focus on another source of asynchronous peripheral speed of wheels of a wheel-set. It is given by railway vehicle wheel conicity. It will be shown, how the contact circle diameter change influences the torsion load of the wheel-set axle and the load type.S rostoucím významem kolejové dopravy rostou také nároky na ekonomiku a funkčnost jejího provozu. Ty jsou ovlivňovány řadou faktorů, jejichž identifikace, přímé zjišťování a dopad je v reálném provozu velmi obtížné měřit nebo dlouhodobě sledovat. Počítačová simulace a kladkový stav jsou vhodnými prostředky, kterými lze rozpoznat míru vlivu fyzikálních omezení ve spojení s navrhovanou konstrukcí vozidla a s předpokládanými okolními podmínkami provozu vše vyjasnit před uvedením vozidla do vlastního provozu. Proto byl v rámci SGS (studentská grantová soutěž) a doktorských studijních programů sestaven, používán a rozvíjen model v Simulinku zaměřený na oblast výzkumu torzní dynamiky hnaných náprav a vlivu adhezních podmínek. V minulosti sloužil ke zkoumání torzního kmitání buzeného změnami přenosu krouticího momentu. V tomto článku se zaměřujeme na jiný zdroj asynchronní obvodovou rychlost kol dvojkolí. To je dáno kuželovitostí kol kolejových vozidel. Bude ukázáno, jak změna průměru kontaktní kružnice ovlivňuje torzní zatížení osy dvojkolí a druh zatížení

Gaming security by obscurity

Shannon sought security against the attacker with unlimited computational powers: *if an information source conveys some information, then Shannon's attacker will surely extract that information*. Diffie and Hellman refined Shannon's attacker model by taking into account the fact that the real attackers are computationally limited. This idea became one of the greatest new paradigms in computer science, and led to modern cryptography. Shannon also sought security against the attacker with unlimited logical and observational powers, expressed through the maxim that "the enemy knows the system". This view is still endorsed in cryptography. The popular formulation, going back to Kerckhoffs, is that "there is no security by obscurity", meaning that the algorithms cannot be kept obscured from the attacker, and that security should only rely upon the secret keys. In fact, modern cryptography goes even further than Shannon or Kerckhoffs in tacitly assuming that *if there is an algorithm that can break the system, then the attacker will surely find that algorithm*. The attacker is not viewed as an omnipotent computer any more, but he is still construed as an omnipotent programmer. So the Diffie-Hellman step from unlimited to limited computational powers has not been extended into a step from unlimited to limited logical or programming powers. Is the assumption that all feasible algorithms will eventually be discovered and implemented really different from the assumption that everything that is computable will eventually be computed? The present paper explores some ways to refine the current models of the attacker, and of the defender, by taking into account their limited logical and programming powers. If the adaptive attacker actively queries the system to seek out its vulnerabilities, can the system gain some security by actively learning attacker's methods, and adapting to them?Comment: 15 pages, 9 figures, 2 tables; final version appeared in the Proceedings of New Security Paradigms Workshop 2011 (ACM 2011); typos correcte

Models of everywhere revisited: a technological perspective

The concept ‘models of everywhere’ was first introduced in the mid 2000s as a means of reasoning about the environmental science of a place, changing the nature of the underlying modelling process, from one in which general model structures are used to one in which modelling becomes a learning process about specific places, in particular capturing the idiosyncrasies of that place. At one level, this is a straightforward concept, but at another it is a rich multi-dimensional conceptual framework involving the following key dimensions: models of everywhere, models of everything and models at all times, being constantly re-evaluated against the most current evidence. This is a compelling approach with the potential to deal with epistemic uncertainties and nonlinearities. However, the approach has, as yet, not been fully utilised or explored. This paper examines the concept of models of everywhere in the light of recent advances in technology. The paper argues that, when first proposed, technology was a limiting factor but now, with advances in areas such as Internet of Things, cloud computing and data analytics, many of the barriers have been alleviated. Consequently, it is timely to look again at the concept of models of everywhere in practical conditions as part of a trans-disciplinary effort to tackle the remaining research questions. The paper concludes by identifying the key elements of a research agenda that should underpin such experimentation and deployment