Reliability in mechanical systems projects

Sufficient safety of the parts, which determines the safety of the system specified by the technical assignment, is the necessary quality of the project, the subject of the design engineer’s attention and the customer’s requirement. An extensive task is the collection of data for iterative refinement of the resource for project details in a probabilistic aspect. It can be significantly reduced when using approximate methods for estimating the resource at intermediate stages of refining the project to the required resource with a calculated probability of failure-free operation. Thus, by the analysis of dimensionless relations of parameters of models of fatigue damage development, it is possible to obtain tools of numerical estimation of technological and constructive techniques of increase of a resource of details and their rational combination. The paper deals with the numerical measures of various directions of upgrading the fatigue life of the parts, derived from the dimensionless relations of the parameters of fatigue damage development models.

Dogs (canis familiaris) underestimate the quantity of connected items: first demonstration of susceptibility to the connectedness illusion in non-human animals

In humans, numerical estimation is affected by perceptual biases, such as those originating from the spatial arrangement of elements. Different animal species can also make relative quantity judgements. This includes dogs, who have been proposed as a good model for comparative neuroscience. However, dogs do not show the same perceptual biases observed in humans. Thus, the exact perceptual/cognitive mechanisms underlying quantity estimations in dogs and their degree of similarity with humans are still a matter of debate. Here we explored whether dogs are susceptible to the connectedness illusion, an illusion based on the tendency to underestimate the quantity of interconnected items. Dogs were first trained to choose the larger of two food arrays. Then, they were presented with two arrays containing the same quantity of food, of which one had items interconnected by lines. Dogs significantly selected the array with unconnected items, suggesting that, like in humans, connectedness determines underestimation biases, possibly disrupting the perceptual system’s ability to segment the display into discrete objects. The similarity in dogs’ and humans’ susceptibility to the connectedness, but not to other numerical illusions, suggests that different mechanisms are involved in the estimation of quantity of stimuli with different characteristics.

Secure Federated Aggregate-Count Queries on Medical Patient Databases Using Fully-Homomorphic Cryptography

Electronic health records (EHR) are often siloed across a network of hospitals, but researchers may wish to perform aggregate count queries on said records in entirety---e.g. How many patients have diabetes? Prior work has established a strong approach to answering these queries in the form of probabilistic sketching algorithms like LogLog and HyperLogLog; however, it has remained somewhat of an open question how these algorithms should be made truly private. While many works in the computational biology community---as well as the computer science community at large---have attempted to solve this problem using differential privacy, these methods involve adding noise and still reveal some amount of non-trivial information. Here, we prototype a new protocol using fully homomorphic encryption that is trivially secured even in the setting of quantum-capable adversaries, as it reveals no information other than that which can be trivially gained from final numerical estimation. Simulating up to 16 parties on a single CPU thread takes no longer than 20 minutes to return an estimate with expected 6% approximation error; furthermore, the protocol is parallelizable across both parties and cores, so, in practice, with optimized code, we might expect sub-minute processing time for each party.

NUMERICAL ESTIMATION OF THERMAL STABILITY BOUNDARIES OF FIXED BED BIOMASS COMBUSTION USING LOCAL CHEMICAL EQUILIBRIUM APPROXIMATION

В статье исследуется зависимость стационарной температуры слоевого горения биомассы от скорости подачи и удельного расхода воздушного дутья. Для этого стационарное уравнение теплового баланса вместе с простейшим уравнением кинетики для химической реакции решается в широком диапазоне параметров. Для численного решения вводится ряд допущений (узкая зона реакции, преимущественный отвод теплоты путем лучистой теплопроводности, равновесный состав продуктов окисления). Результаты расчетов дают граничные значения расходных и стехиометрических параметров, при которых возможно устойчивое горение. The article investigates the dependence of the stationary combustion temperature of layer combustion of biomass on the feed rate and specific consumption of air blast. For this, the stationary heat balance equation, together with the simplest kinetic equation for a chemical reaction, is solved over a wide range of parameters. For a numerical solution, a number of assumptions are introduced (a narrow reaction zone, preferential heat removal by radiant heat conduction, equilibrium composition of oxidation products). The calculation results give the boundary values of the consumption and stoichiometric parameters at which stable combustion is possible.