Zoekresultaten

Modeling of cavity wall metal ties for defining seismic response of Groningen houses

Architecture Compliance Checking of Semantically Rich Modular Architectures

Abstract-Architecture Compliance Checking (ACC) is an approach to verify the conformance of implemented program code to high-level models of architectural design. ACC is used to prevent architectural erosion during the development and evolution of a software system. Static ACC, based on static software analysis techniques, focuses on the modular architecture and especially on rules constraining the modular elements. A semantically rich modular architecture (SRMA) is expressive and may contain modules with different semantics, like layers and subsystems, constrained by rules of different types. To check the conformance to an SRMA, ACC-tools should support the module and rule types used by the architect. This paper presents requirements regarding SRMA support and an inventory of common module and rule types, on which basis eight commercial and non-commercial tools were tested. The test results show large differences between the tools, but all could improve their support of SRMA, what might contribute to the adoption of ACC in practice.

On the Accuracy of Architecture Compliance Checking Support

Abstract-Architecture Compliance Checking (ACC) is useful to bridge the gap between architecture and implementation. ACC is an approach to verify conformance of implemented program code to high-level models of architectural design. Static ACC focuses on the modular software architecture and on the existence of rule violating dependencies between modules. Accurate tool support is essential for effective and efficient ACC. This paper presents a study on the accuracy of ACC tools regarding dependency analysis and violation reporting. Seven tools were tested and compared by means of a custom-made test application. In addition, the code of open source system Freemind was used to compare the tools on the number and precision of reported violation and dependency messages. On the average, 74 percent of 34 dependency types in our custom-made test software were reported, while 69 percent of 109 violating dependencies within a module of Freemind were reported. The test results show large differences between the tools, but all tools could improve the accuracy of the reported dependencies and violations.

Quantification of damage evolution in masonry walls subjected to induced seismicity

This paper aims to quantify the evolution of damage in masonry walls under induced seismicity. A damage index equation, which is a function of the evolution of shear slippage and opening of the mortar joints, as well as of the drift ratio of masonry walls, was proposed herein. Initially, a dataset of experimental tests from in-plane quasi-static and cyclic tests on masonry walls was considered. The experimentally obtained crack patterns were investigated and their correlation with damage propagation was studied. Using a software based on the Distinct Element Method, a numerical model was developed and validated against full-scale experimental tests obtained from the literature. Wall panels representing common typologies of house façades of unreinforced masonry buildings in Northern Europe i.e. near the Groningen gas field in the Netherlands, were numerically investigated. The accumulated damage within the seismic response of the masonry walls was investigated by means of representative harmonic load excitations and an incremental dynamic analysis based on induced seismicity records from Groningen region. The ability of this index to capture different damage situations is demonstrated. The proposed methodology could also be applied to quantify damage and accumulation in masonry during strong earthquakes and aftershocks too.

Experimental characterization of timber joist-masonry connections

Out-of-plane (OOP) wall collapse is one of the most common failure mechanismsin unreinforced masonry (URM) structures. Insufficient connections at wall-to-wall, wall-to-floor or wall-to-roof levels are one of the main reasons for OOP failures. The seismic assessment of URM buildings with insufficient connections became of high relevance. In particular, cavity walls are widely used in many regions, such as Central and Northern Europe, Australia, New Zealand, China, and Groningen in the Netherlands. Defining thus the behaviour of such connections is of prime importance to understand the overall response of URM buildings.This paper is about an experimental campaign conducted at the BuildinG laboratory of Hanze University of Applied Sciences on timber joist-masonry connections, reproducing cavity walls with timber joists in as-built condition. A total of six URM tests were performed, with varying configurations as: two different tie distributions, two precompression levels and two different as-built connections. The tests aim at providing a complete characterization of the behaviour of the timber-joist cavity-wall connections under axial cyclic loading with special attention on the developed failure mechanism and the definition of force-displacement curves for each group of tests performed. The experimental results show that cohesion and friction between joist and masonry are important parameters in terms of the governing failure mechanism, whether it is a joist-sliding or rocking failure.

Influencing nursing students' perceptions of community care with curriculum-redesign; a quasi-experimental cohort study

Background: The shift in healthcare to extramural leads to more patients with complex health problems receiving nursing care at home. However, the interest of baccalaureate nursing students for community nursing is moderate, which contributes to widespread labour-market shortages. This study investigates the effect of a more ‘communitycare-oriented’ curriculum on nursing students’ perceptions of community care. Methods: A quasi-experimental quantitative survey study with a historic control group (n = 477; study cohorts graduating in 2015, 2016, and 2017; response rate 90%) and an intervention group (n = 170; graduating in 2018; response rate 93%) was performed in nursing students of a University of Applied Sciences in a large city in the Netherlands. The intervention group underwent a new curriculum containing extended elements of community care. The primary outcome was assessed with the Scale on Community Care Perceptions (SCOPE). The control and intervention group were compared on demographics, placement preferences and perceptions with a chi-square or T-test. Multiple regression was used to investigate the effect of the curriculum-redesign on nursing students’ perceptions of community care.Results: The comparison between the control and intervention group on students’ perceptions of community care shows no significant differences (mean 6.18 vs 6.21 [range 1–10], respectively), nor does the curriculum-redesign have a positive effect on students’ perceptions F (1,635) = .021, p = .884, R2 = < .001. The comparison on placement preferences also shows no significant differences and confirms the hospital’s popularity (72.7% vs 76.5%, respectively) while community care is less often preferred (9.2% vs 8.2%, respectively). The demographics ‘working in community care’ and ‘belonging to a church/religious group’ appear to be significant predictors of more positive perceptions of community care. Conclusions: Graduating students who experienced a more ‘community-care-oriented’ curriculum did not more often prefer community care placement, nor did their perceptions of community care change. Apparently, four years of education and placement experiences have only little impact and students’ perceptions are relatively static. It would be worth a try to conduct a large-scale approach in combination with a carefully thought out strategy, based on and tying in with the language and culture of younger people. Keywords: Community care, Nurse education, Curriculum design, Perceptions, Career choice