for a graph g, let d(g) be the set of all strong orientations of g. the orientationnumber of g is min {d(d) |d belongs to d(g)}, where d(d) denotes the diameterof the digraph d. in this paper, we determine the orientation number for some subgraphs of complete bipartite graphs.

Linear elastic fracture mechanics predicts that joint orientation is controlled by the stress field in which the joints propagate. Thus joint sets are effective proxies for stress trajectories during joint growth. Complexity in joint orientation indicates stress trajectory variability, a phenomenon quantified using an eigenvalue method that measures dispersion of joint normal vectors (i.e. pole...

For the purpose of exploring deformation characteristics of jointed rock masses, influence of joint inclination and confining pressure on the mechanical behavior of discontinuous rock a series of compression tests were conducted under satisfactory testing conditions on three types of sandstone from various locations. Three groups of jointed specimens were used in this research, including specim...

It is known that epipolar constraint can be augmented with orientation by formulating it in the oriented projective geometry. This oriented epipolar constraint requires knowing the orientations (signs of overall scales) of epipoles and fundamental matrix. The current belief is that these orientations cannot be obtained from the fundamental matrix only and that additional information is needed, ...

This paper presents a method for the autonomous calibration of six degrees-of-freedom parallel robots. The calibration makes use of the motorized prismatic joint positions corresponding to some sets of configurations where in each set either a passive Universal joint or a passive Spherical joint is fixed using a lock mechanism. Simulations give us an idea about the number of sets that must be u...

STUDY DESIGN Cross-sectional study of healthy volunteers. PURPOSE We aimed to investigate the variation in the lumbar facet joint orientation in an adult Asian population. The relationship between the facet joint orientation and muscle cross-sectional area (CSA) of multifidus and erector spinae was also clarified. OVERVIEW OF LITERATURE Several studies have reported that lumbar pathologies,...

Wolff's law of trajectorial orientation proposes that trabecular struts align with the orientation of dominant compressive loads within a joint. Although widely considered in skeletal biology, Wolff's law has never been experimentally tested while controlling for ontogenetic stage, activity level, and species differences, all factors that may affect trabecular bone growth. Here we report an exp...

This experiment was carried out to test the hypothesis that three-dimensional upper limb movements could be initiated and controlled in the joint space via a mechanism comparing an estimate of the current postural state of the upper arm with a target value determined by one specific inverse static transform converting the coordinates of the object into a set of arm, forearm, and wrist angles. T...