"The competitive environment has become more challenging due to pricing pressure, which has intensified in Europe since September, and the unfavorable impact on the country mix of the fall-off in demand in southern Europe," the company said.
The publisher warned that the year-on-year "comparatives during the second half of the year will be more challenging due to the benefit of the 2012 Olympics and the significant production cost savings which were realised during the second half of last year".
In MANET, security is more challenging due to problems related to key exchange.
For example, contact tracing has recently become more challenging due to relocation of contacts from urban to rural communities (28).
Fitting Gaussians to the B-cations is more challenging, due to the A-cations being more intense.
The cloud images in the IapCAS-E database are more challenging due to the influence factors of aerosol and noise.
The use of fibers in pervious concrete is even more challenging due to high porosity and insufficient fiber-matrix bonding interface.
For municipal wastewaters, it is more challenging due to the lower carbon load, and potentially lower yield of methane per unit carbon (Cakir and Stenstrom 2005).
More recently, the turbo approach has been proposed also for doubly selective channel equalization, which is more challenging due to the time variation of the channel.
We also present strong scaling results for cosmo25 and dwarf datasets, which are more challenging due to their highly clustered nature.
Thus, timing synchronization in OFDM systems becomes much more challenging due to the increase in the amount of inter-carrier interference (ICI) and inter-symbol interference (ISI [1].
