Abstract

"jats:p"The problem of safety of the flight operations will be valid as long as there will be aviation, both civil and military. Ensuring the safety was, is and will be one the most important issues in the functioning and development of aviation."/jats:p" "jats:p"The safety of flight operations affect the implementation of all the elements involved in this process, which can be summarized in three groups, namely: man, the aircraft and the environment, including "jats:bold"airfield pavements"/jats:bold". Airfield pavements are elements that can be intentionally destroyed by military action as well as a result of random unexpected situation (failure, catastrophe, natural disaster). The reconstruction of airfield pavements in crisis situations and in military operations should enable to restore the operational availability of destroyed elements in the shortest possible time. Document type: Article

Abstract

W referacie przedstawiono wyniki badań, których celem było opracowanie metody diagnozowania okrętowych szybkoobrotowych silników tłokowych. Polska Marynarka Wojenna eksploatuje znaczną liczbę silników tego typu również na okrętach podwodnych. Silniki tego typu nie posiadają zaworów indykatorowych, co komplikuje możliwość oceny procesu spalania i ich stanu technicznego. Akademia Marynarki Wojennej w Gdyni od lat prowadzi badania związane z rozwojem metod diagnozowania okrętowych tłokowych silników spalinowych. W ostatnich latach prowadzone są prace nad metodami diagnozowania szybkoobrotowych silników okrętowych bazującymi na analizie obwiedni przyspieszeń drgań generowanych przez układy rozrządu zaworowego i układ paliwowy. W referacie zaprezentowano wybrane wyniki badań prowadzonych na silnikach Mercedes-Maybach typu MB820 stosowanych na okrętach podwodnych klasy Kobben. Document type: Article

Abstract

Vulnerable road users (VRUs) represent a large portion of fatalities and injuries occurring on European Union roads. It is therefore important to address the safety of VRUs, particularly in urban areas, by identifying which factors may affect the injury severity level that can be used to develop countermeasures. This paper aims to identify the risk factors that affect the severity of a VRU injured when involved in a motor vehicle crash. For that purpose, a comparative evaluation of two machine learning classifiers&mdash decision tree and logistic regression&mdash considering three different resampling techniques (under-, over- and synthetic oversampling) is presented, comparing both imbalanced and balanced datasets. Crash data records were analyzed involving VRUs from three different cities in Portugal and six years (2012&ndash 2017). The main conclusion that can be drawn from this study is that oversampling techniques improve the ability of the classifiers to identify risk factors. On the one hand, this analysis revealed that road markings, road conditions and luminosity affect the injury severity of a pedestrian. On the other hand, age group and temporal variables (month, weekday and time period) showed to be relevant to predict the severity of a cyclist injury when involved in a crash. Document type: Article