86,731 research outputs found
Strategies in modular system design by interface rewriting
No full textThe design of a modular system using a predefined set of modules with a given import or export interface, has been reduced to the problem of generating a specification in an algebraic specification grammar. In this paper we provide not only syntactical criteria (independent of the target specification) for avoiding unnecessary searches, but also a strategy to adopt in choosing the rewrite rules. The former development has been influenced by similar work on graph grammars, whereas we introduce the concepts of similarity between specifications and a definition of value in order to guide the search algorithm for the latter. A further development of the similarity concept allows to consider a set of specification as a metric space, giving a precise definition of distance function
An Algebraic Theory of Class Specifications
No full textThe notion of class (or object pattern) as defined in most object-oriented languages is forrnahzed using known techniques from algebraic specifications, Inheritance can be viewed as a relation between classes, which suggests how classes can be arranged in hierarchies. The hierarchies contain two kinds of reformation: on the one hand, they indicate how programs are structured and how code is shared among classes; on the other hand, they give information about compati- ble assignment rules, which are based on subtyping. In order to distinguish between code sharing, which is related to lmplementatlonal aspects, and functional speclalizatlon, which is connected to the external behavior of objects, we introduce an algebraic specification-based formalism, by which one can specify the behavior of a class and state when a class inherits another one. It is shown that reusing inheritance can be reduced to specialization inheritance with respect to a virtual class The class model and the two distinct aspects of inheritance allow the defimtion of clean interconnection mechanisms between classes leading to new classes which mherlt from old classes them correctness and their semantics
Combination therapies for improved management of lower urinary tract symptoms/benign prostatic hyperplasia
No full textSeveral urological and nonurological conditions can contribute to the onset of lower urinary tract symptoms (LUTS), including benign prostatic hyperplasia (BPH), which is one of the main underlying causes in male patients. Six pharmacological classes (α-adrenoceptor blockers [ABs], 5α-reductase inhibitors [5ARIs], phytotherapeutics, antimuscarinics [AMs], β3-adrenoceptor agonists and phosphodiesterase type 5 inhibitors [PDE5Is]) are available, alone or in combination, for the treatment of male LUTS. The aim of this review is to summarize the latest evidence on combination medical treatments for male patients with LUTS/BPH. Standard combinations include AB + 5ARI (for patients with increased prostate volume who are at risk for BPH progression); AB + PDE5I (for patients with concomitant erectile dysfunction); and AB + AM or β3 agonist (for patients with persistent storage symptoms and not at risk for acute urinary retention). Other possible multidrug treatments have been proposed in preliminary studies, but further randomized controlled trials are needed to determine whether these putative strategies will eventually be considered a new standard for patients with LUTS/BPH. The possibility of tailoring BPH treatment according to different patient characteristics and expectations, using two or more drugs, seems a promising path in the field of LUTS/BPH management; however, physicians should consider the risk of increasing costs without proven long-term efficacy with most of these combination treatments
Proposal for Tip Relief Modification to Reduce Noise and Sensitivity to Meshing Conditions in Spur Gears
No full textIn this article, a new tip relief profile modification for spur gears is presented. The topography proposed here is a classical linear profile modification with a parabolic fillet (linear-parabolic modification). The parabolic fillet extension is treated as a parameter and its effect investigated.
The proposed topography combines advantages from both linear and parabolic tip relief. The evolution from linear to parabolic is discussed in terms of peak-to-peak transmission error. Anomalous contact conditions due to particular tip relief modifications are reported,and maps are obtained in order to find optimum tip relief by taking into account contact condition boundaries
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