background: in process industries, production, storage, transportation, usage and disposal of chemicals are inherently dangerous and the risk of catastrophic accident occurrence is potentially high. to improve safety level in these industries, establishment of process safety management (psm) system is considered as the most effective measures. this study was conducted to determine the degree of...

background: this study investigated the relationship between people's attitudes towards the safety culture and comparing its perceptions among three levels of refinery personnel: top management, supervisory staff and frontline workers by conducting safety culture survey. methods: a questionnaire comprising general information and 59-safety attitude statement were distributed among 237 workers, ...

The introduction of the Internet at schools has raised new pedagogical challenges facing educators trying to ensure children’s awareness of the possible dangers when surfing the Web. This article aims to investigate how teachers evaluate the possible dangers that students might face when surfing the Net for various educational or interpersonal purposes, and the teachers’ technological skills in...

Covariant types are a powerful language feature for improving type-safety. However, covariant types complicate type-checking when combined with polymorphism. We propose two new language features that can improve type-checking in a language with polymorphism and covariant typing, and also have the potential to improve efficiency as well. Published by Elsevier Ltd.

Dan Ma 1,2,3,*, Qiang Li 2, Matthew R. Hall 3,4 and Yu Wu 2 1 School of Resources & Safety Engineering, Central South University, Changsha 410083, Hunan, China 2 State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining & Technology, Xuzhou 221116, Jiangsu, China; [email protected] (Q.L.); [email protected] (Y.W.) 3 GeoEnergy Research Centre (GERC), U...

The obsolescence problem (component life of 7 years, compared to aircraft life of 30+ years) whilst maintaining high-capability and low–cost upgrades is the holy grail for avionics systems integrators. The use of COTS and getting maximum reuse of existing functionality is key to solving this problem. However, such an approach can compromise the certification basis of the aircraft. The originall...

We present a type system that naturally couples two diierent, and apparently contradictory, notions of inheritance that occur in object-oriented databases. To do this we distinguish between the type and a kind of a value. A type describes the entire structure of a value, while a kind describes only the availability of certain elds or methods. This distinction allows us to manipulate heterogeneo...

This paper investigates the effects of macroeconomic volatility on non–financial firms’ cash holding behavior. Using an augmented cash buffer–stock model, we demonstrate that an increase in macroeconomic volatility will cause the cross–sectional distribution of firms’ cash–to–asset ratios to narrow. We test this prediction on a panel of non–financial firms drawn from the annual COMPUSTAT databa...

There is a constant demand for improved performance of fighter aircraft as there is a rapid change in threat scenario. There is need for advanced flight control system to meet this demand for providing improved performance with ease of maintenance. This paper brings out the advanced distributed digital flight control system with built in prognosis features. It also compares the architectural fe...