An experimental comparative study of various controllers for a class of ac–dc converters, known as power factor precompensators (PFP) is presented. The control objective is to robustly regulate the output voltage to a desired constant level in the presence of variations in the load, while retaining a unit power factor at the input, i.e., the input current should follow in frequency and in phase...

Introduction: The different factors that affect the camera uniformity of Single Photon Emission Computed Tomography (SPECT) technique have been analyzed including peak shift (%) and window width of energy. The effect of peak shift and window width on SPECT image uniformity has been investigated using a point source to perform intrinsic flood images. Methods:</stro...

The width measure treedepth, also known as vertex ranking, centered coloring and elimination tree height, is a well-established notion which has recently seen a resurgence of interest. Since graphs of bounded treedepth are more restricted than graphs of bounded treeor pathwidth, we are interested in the algorithmic utility of this additional structure. On the negative side, we show with a novel...

Over the last 30 years, researchers have investigated connections between dimension for posets and planarity for graphs. Here we extend this line of research to the structural graph theory parameter tree-width by proving that the dimension of a finite poset is bounded in terms of its height and the tree-width of its cover graph.

background: the foramen magnum (fm) is an important landmark of the skull base and a transition zone between spine and skull as well as its close relationship to the brain and the spinal cord. so the fm has gained considerable interest due to its comparative anatomy, ontogeny, clinical, and animal breeding viewpoints. objectives: the aim of this study was to determine morphology and morphometry...

to conserve the genetic resources and identify the strong and weak points in sistan watermelon accessions and compare these with improved cultivars of: sugarbaby and fairfax, an experiment was carried out, based on rectangular lattic design of two replications in 2007. the morphological traits studied, included plant length, plant weight, seed weight, fruit number, fruit length, fruit width, su...

Several variants of Multicut problems arise in applications like circuit and network design. In general, these problems are NP-complete. The goal of our work is to investigate the potential of clique-width for identifying tractable fragments of Multicut. We show for several parameterizations involving clique-width whether they lead to tractability or not. Since bounded tree-width implies bounde...

introduction: scatter radiation is one of the major sources of error in nuclear medicine data processing. different methods of scatter correction have been introduced in order to improve the quality of data. however the best method is to avoid recording of scatter photons in acquisition. the only difference between scattered and non-scattered photons is the energy. pulse height analyzer is the ...

objective ultrasonography is among the most general evaluating methods for central nervous system (cns) assessment, especially for detecting extra axial collection via anterior fontanel. there are few studies showing values of this technique in normal developing infants for detection of subarachnoid space width. association between age and sex and cerebrospinal fluid (csf) spaces are controvers...