statement of problem: digital subtraction radiography (dsr) needs reproducible alignment between the x-ray source, the object, and the film for obtaining identical projections of the same anatomic region. purpose: the aim of this study was to evaluate the effect of bite registrations (placed on individual bite blocks) on the reproducibility of parallel periapical radiographs, obtained every 2 m...

Series-parallel orders are deened as the least class of partial orders containing the one-element order and closed by ordinal sum and disjoint union. From this inductive deenition, it is almost immediate that any series-parallel order may be represented by an algebraic expression, which is unique up to the associativity of ordinal sum and to the associa-tivivity and commutativity of disjoint un...

The inseparability graph of an oriented matroid is an invariant of its class of orientations. When an orientable matroid has exactly one class of orientations the inseparability graph of all its orientations is in fact determined by its non-oriented underlying matroid. From this point of view it is natural to ask if inseparability graphs can be used to characterize matroids which have exactly o...

For the sake of high-efficiency energy recycling and brake security for series-parallel hybrid electric vehicle, an integrated brake system with an electric consuming brake subsystem and advanced strategy is proposed. The specific structure of electric consuming brake subsystem is introduced. The brake processes in different brake conditions are analyzed. A brake control strategy relying on the...