A history-based scheme for accelerating Prolog interpretation

An algorithm for improving the performance of a Prolog interpreter is introduced. The algorithm, unlike the intelligent backtracking schemes which improve the performance by avoiding redundant redos, avoids redundant calls. The algorithm identifies the redundant calls by maintaining a history of the program execution. The algorithm can be used in conjunction with an intelligent backtracking scheme for a further speed-up of the programs

Gravity-induced shear force in reinforced concrete walls above transfer structures

In this study, the gravity loads in reinforced concrete shear walls supported on transfer structures are investigated. Emphasis is placed on the shear-stress concentration effects on the supported shear walls owing to the distortion of the transfer structure. A simplified model is proposed to illustrate the fundamental physical interactions. Finite-element analysis is also conducted to study the influences of the symmetric and asymmetric shear-wall arrangements, positioning of supporting columns and span-to-depth ratio of the transfer structure. Non-linear behaviours encompassing the use of yielded stiffness at ultimate limit state, sequential construction and the creep of reinforced concrete under gravity loads are addressed. Various effects of modelling assumptions and simplifications on the stress redistribution of the transfer structure are investigated. Remedial measures are proposed, such as increasing the depth of the transfer girders using late-cast slabs, segmented upper shear walls and concrete of higher grade for critical regions.published_or_final_versio

Shear and flexural stiffnesses of reinforced concrete shear walls subjected to cyclic loading

Abstract: Seismic analyses of concrete structures under maximum-considered earthquakes require the use of reduced stiffness accounting for cracks and degraded materials. Structural walls, different to other flexural dominated components, are sensitive to both shear and flexural stiffness degradations. Adoption of the gross shear stiffness for walls in seismic analysis prevails particularly for the design codes in the US. Yet available experimental results indicate that this could overstate the shear stiffness by more than double, which would hamper the actual predictions of building periods and shear load distributions among columns and walls. In addition, the deformation capacity could be drastically understated if the stipulated constant ductility capacity is adopted. This paper reviews the available simplified shear and flexural models, which stem from classical mechanics, empirical formulations and/or parametric studies, suitable for structural walls at the state-of-the-art. Reviews on the recommended flexural and shear stiffnesses by prominent design codes such as ACI318-11, Eurocode 8 and CSA are included. A database comprised of walls subjected to reverse-cyclic loads is formed to evaluate the performance of each model. It is found that there exist classical models that could outweigh overconservative codified values with comparable simplicity for practical uses.published_or_final_versio

Curve Matching by Using B-spline Curves

This paper presents an algorithm for estimating the control points of the B-spline and curve matching which are achieved by using the dissimilarity measure based on the knot associated with the B-spline curves. The B-splines stand as one of the most efficient curve representations and possess very attractive properties such as spatial uniqueness, boundedness and continuity, local shape controllability, and invariance to affine transformations. These properties made them very attractive for curve representation. Consequently, they have been extensively used in computer-aided design and computer graphics. The curve-matching program is shown in detail in this paper. Any input test object curve can be matched with the B-spline sample curve. The control points of sample curve are computed and stored in the program. The test object curve, a bitmap file, is thinned, then converted to B-spline curve and then to match with the sample curve

Evidence-based policy on dietary calcium and vitamin D

Copyright © 2011 American Society for Bone and Mineral Research.Peer reviewedPostprin

Surgical management of a drooling child

Drooling is a physiological process in infants. When it persists beyond the age of 4 years, it becomes a clinical symptom. Drooling is a common problem among children of all ages with a neurological deficit. It causes significant decrease in the quality of life of the children and their families. Parents often accept the disability because they are not aware that treatment is available. Doctors should recognise the problem during a consultation and discuss the available management options. Patients should be reffered to a drooling clinic that adopts a multi-disciplinary approach. Management of drooling has been evolving over the last thirty years. Surgery has become a safe and effective management option.published_or_final_versio