introduction drastic model is an index and overlapping model that has been designed for producing vulnerability scores for different points by combining several thematic layers. overlapping distinguished methods are themost applicable methods for evaluatingvulnerability of aquifers because they are cheap, they can directly reach a defined goal, the used data in the methods are accessible or can...

due to simple operation and no needs for expensive infrastructure construction to convey water from a source to farm lands, groundwater becomes the most important sources of agricultural water supply in iran. however, the contamination of aquifers is a major concern in many countries, specifically in areas without effective groundwater protection and management. therefore, groundwater vulnerabi...

background: groundwater nitrate pollution is an important environmental problem in water resources management. in this regard, specific measures aiming at prevention of water pollution will be helpful to managers and decision-makers. identification of aquifers’ vulnerable areas and determination of groundwater protection zones using most widely used models, such as drastic and cd, are one of th...

The analysis of vulnerability in networks generally involves some questions about how the underlying graph is connected. One is naturally interested in studying the types of disruption in the network that maybe caused by failures of certain links or nodes. In terms of a graph, the concept of connectedness is used in dierent forms to study many of the measures of vulnerability. When certain vert...

the analysis of vulnerability in networks generally involves some questions about how the underlying graph is connected. one is naturally interested in studying the types of disruption in the network that maybe caused by failures of certain links or nodes. in terms of a graph, the concept of connectedness is used in dierent forms to study many of the measures of vulnerability. when certain ver...

In the paper we simulate web-system availability taking into account security aspects and different maintenance scenarios. As a case study we have developed two Markov’s models. These models simulate availability of a multitier web-system considering attacks on DNS vulnerabilities in additional to system failures due to hardware/software (HW/SW) faults. Proposed Markov’s model use attacks rate ...