The attainment of high reliability and availability is very difficult to be achieved in very complex wireless infrastructureless networks.
Availability is thus difficult to evaluate [ 31].
Moreover, since the availability of GPS signals is difficult to be guaranteed, some backup synchronized timing sources can be used, such as network time protocol (NTP), e-Loran, and chip scale atomic clock (CSAC).
The impact on soil invertebrates of changes in the physical environment and feed availability in intensive pastoral systems is difficult to predict given the number of interacting factors.
A secular increase in nutrients, or an increase in nutrient availability as an alternative trigger is difficult to demonstrate, and the diversity curves of the fossil phytoplankton [66] are an unreliable measure of the bioproductivity.
In some cases, it was not feasible to establish the reasons for the withdrawal, for example, astemizole has been withdrawn from the UK, France and Spain, but information about its availability in other EU countries is difficult to establish.
Anyhow, with minimally invasive methods, the accuracy in the diagnosis of sinus membrane perforation is difficult without the availability of endoscope.
Considering the availability of various access technologies, it is difficult for a network operator to find reliable criteria to select the best network that ensures user satisfaction while reducing multiple network selection.
Over the course of my professional journey, I have identified two very important problems: Availability and affordability of good data is difficult, and expertise in how to tell the right story through data is often lacking.
Most high-fashion shoppers know what they want and they want it now, but access to information around availability can be difficult to come by.
