Brno University of Technology

About: Brno University of Technology is a education organization based out in Brno, Czechia. It is known for research contribution in the topics: Fracture mechanics & Filter (video). The organization has 6339 authors who have published 15226 publications receiving 194088 citations. The organization is also known as: Vysoké učení technické v Brně & BUT.

Healing data races on-the-fly

Abstract: Testing of concurrent software is extremely difficult. Despite all the progress in the testing and verification technology, concurrent bugs, the most common of which are deadlocks and races, make it to the field. This paper describes a set of techniques, implemented in a tool called ConTest, allowing concurrent programs to self-heal at run-time. Concurrent bugs have the very desirable property for healing that some of the interleaving produce correct results while in others bugs manifest. Healing concurrency problems is about limiting, or changing the probability of interleaving, such that bugs will be seen less. When healing concurrent programs, if a deadlock does not result from limiting the interleaving, we are sure that the result of the healed program could have been in the original program and therefore no new functional bug has been introduced. In this initial work which deals with different types of data races, we suggest three types of healing mechanisms: (1) changing the probability of interleaving by introducing sleep or yield statements or by changing thread priorities, (2) removing interleaving using synchronisation commands like locking and unlocking certain mutexes or waits and notifies, and (3) removing the result of "bad interleaving" by replacing the value of variables by the one that "should" have been taken. We also classify races according to the relevant healing strategies to apply.

Biomechanical rupture risk assessment of abdominal aortic aneurysms based on a novel probabilistic rupture risk index.

Abstract: A rupture risk assessment is critical to the clinical treatment of abdominal aortic aneurysm (AAA) patients. The biomechanical AAA rupture risk assessment quantitatively integrates many known AAA rupture risk factors but the variability of risk predictions due to model input uncertainties remains a challenging limitation. This study derives a probabilistic rupture risk index (PRRI). Specifically, the uncertainties in AAA wall thickness and wall strength were considered, and wall stress was predicted with a state-of-the-art deterministic biomechanical model. The discriminative power of PRRI was tested in a diameter-matched cohort of ruptured (n = 7) and intact (n = 7) AAAs and compared to alternative risk assessment methods. Computed PRRI at 1.5 mean arterial pressure was significantly (p = 0.041) higher in ruptured AAAs (20.21(s.d. 14.15%)) than in intact AAAs (3.71(s.d. 5.77)%). PRRI showed a high sensitivity and specificity (discriminative power of 0.837) to discriminate between ruptured and intact AAA cases. The underlying statistical representation of stochastic data of wall thickness, wall strength and peak wall stress had only negligible effects on PRRI computations. Uncertainties in AAA wall stress predictions, the wide range of reported wall strength and the stochastic nature of failure motivate a probabilistic rupture risk assessment. Advanced AAA biomechanical modelling paired with a probabilistic rupture index definition as known from engineering risk assessment seems to be superior to a purely deterministic approach.

Techno-economic analysis for biomass supply chain: A state-of-the-art review

Abstract: Given the increasing risk of climate change and depletion of non-renewable energy sources, countries around the world have been looking into energy profile diversification whereby biomass represents one of the most appealing alternatives for energy production feedstock. To attract interest and more investment from industry players into biomass-based industries, comprehensive techno-economic analysis has to be performed. In addition, various uncertainties related to supply chain such as biomass attainability, demand variation, and material price fluctuation, have to be considered in the evaluation to yield more accurate and reliable feasibility estimation. This review paper aims to: (i) provide an overview on the different types of methods or approaches used in the feasibility evaluation of biomass-based industries from the techno-economic point of view, and (ii) outline the supply chain uncertainties that should be incorporated into the evaluation model using a Malaysian case study to illustrate the impact of these uncertainties. Apart from that, some of the unquantifiable uncertainties and risks are critically reviewed in this paper. It was found that 78 % of the reviewed articles opted for mathematical modelling evaluation method with the majority leaning towards mathematical modelling with optimization (i.e., deterministic and stochastic optimization). Furthermore, only a minority had performed stochastic evaluation that incorporates biomass supply chain uncertainties. This review discussed six quantifiable uncertainties, include: (i) biomass availability, (ii) biomass quality, (iii) transportation cost, (iv) market demand, (v) fluctuation of pricing, and (vi) wages of workers.

Microalgae: Fast-Growth Sustainable Green Factories

Abstract: Microalgae are definitely on the way to become a sustainable, fast-growing natural green source for highly demanded market products. Research is currently looking at promising outstanding applications of microalgae among which are the production of biofuels from the fatty acids present in biomass, functional foods enriched with microalgae healthy bioactive molecules, and greenhouse gas mitigation (CO2 consuming) based on high cell density microalgae cultures technology. Besides, other traditional microalgae applications are currently increasing in competitiveness in a growing market demand for green biomass, in which microalgae are widely recognized as a healthy, sustainable, and biological renewable resource. Among these traditional applications, microalgae are being used to improve the nutritional quality in animal feed, particularly in aquaculture, therapeutic agent source, and antioxidant activity. In addition, microalgae also show to be functional in waste effluents treatment to remove N and P, thus ...