Nonconvex bundle method with application to a delamination problem
- Authors: Dao, Minh , Gwinner, Joachim , Noll, Dominikus , Ovcharova, Nina
- Date: 2016
- Type: Text , Journal article
- Relation: Computational optimization and applications Vol. 65, no. 1 (2016), p. 173-203
- Full Text: false
- Reviewed:
- Description: Delamination is a typical failure mode of composite materials caused by weak bonding. It arises when a crack initiates and propagates under a destructive loading. Given the physical law characterizing the properties of the interlayer adhesive between the bonded bodies, we consider the problem of computing the propagation of the crack front and the stress field along the contact boundary. This leads to a hemivariational inequality, which after discretization by finite elements we solve by a nonconvex bundle method, where upper- C 1 criteria have to be minimized. As this is in contrast with other classes of mechanical problems with non-monotone friction laws and in other applied fields, where criteria are typically lower- C 1 , we propose a bundle method suited for both types of nonsmoothness. We prove its global convergence in the sense of subsequences and test it on a typical delamination problem of material sciences.
Building STEM in Schools: An Australian Cross-case Analysis
- Authors: Falloon, Garry , Stevenson, Michael , Beswick, Kim , Fraser, Sharon , Geiger, Vincent
- Date: 2021
- Type: Text , Journal article
- Relation: Educational Technology Vol. 24, no. 4 (2021), p. 110-122
- Full Text: false
- Reviewed:
- Description: The Principals as STEM Leaders (PASL) project was an Australian Government-funded national research and professional learning programme for principals, aimed at building STEM leadership capacity. The project involved cluster-based delivery of six learning modules and generation of case studies outlining schools' different approaches to STEM education and STEM leadership. This article analyses factors contributing to the development of four contrasting schools' STEM profiles, identifying the unique approaches and leadership strategies each adopted in designing STEM curriculum for meeting the learning needs of their diverse students. It positions these schools' endeavours within the broader PASL professional learning programme, adding to the limited body of empirical work detailing different approaches schools take to the
Understanding K-12 STEM Education: a Framework for Developing STEM Literacy
- Authors: Falloon, Garry , Hatzigianni, Maria , Bower, Matt , Forbes, Anne , Stevenson, Michael
- Date: 2020
- Type: Text , Journal article
- Relation: Journal of science education and technology Vol. 29, no. 3 (2020), p. 369-385
- Full Text: false
- Reviewed:
- Description: In recent years, arguments have signalled the value of STEM education for building discipline knowledge and an array of capabilities, skills and dispositions, aligned with the needs of young people functioning productively and ethically in dynamic, complex and challenging future work, social and political environments. This combination has been termed STEM literacy and positioned as a desired outcome from STEM education programs. However, knowledge is limited on ways this can be developed in K-12 schools. This article introduces a framework that conceptualises the integrated nature of the characteristics of STEM education. It identifies and maps key characteristics of STEM education, recognising different entry points, curriculum designs and pedagogical strategies for school programs. The framework provides practical guidance for planning and implementing STEM education in schools.
A comprehensive survey of security threats and their mitigation techniques for next‐generation SDN controllers
- Authors: Han, Tao , Jan, Syed Rooh Ullah , Tan, Zhiyuan , Usman, Muhammad , Jan, Mian Ahmad , Khan, Rahim , Xu, Yongzhao
- Date: 2020
- Type: Text , Journal article
- Relation: Concurrency and computation Vol. 32, no. 16 (2020), p. n/a
- Full Text: false
- Reviewed:
- Description: Summary Software Defined Network (SDN) and Network Virtualization (NV) are emerged paradigms that simplified the control and management of the next generation networks, most importantly, Internet of Things (IoT), Cloud Computing, and Cyber‐Physical Systems. The Internet of Things (IoT) includes a diverse range of a vast collection of heterogeneous devices that require interoperable communication, scalable platforms, and security provisioning. Security provisioning to an SDN‐based IoT network poses a real security challenge leading to various serious security threats due to the connection of various heterogeneous devices having a wide range of access protocols. Furthermore, the logical centralized controlled intelligence of the SDN architecture represents a plethora of security challenges due to its single point of failure. It may throw the entire network into chaos and thus expose it to various known and unknown security threats and attacks. Security of SDN controlled IoT environment is still in infancy and thus remains the prime research agenda for both the industry and academia. This paper comprehensively reviews the current state‐of‐the‐art security threats, vulnerabilities, and issues at the control plane. Moreover, this paper contributes by presenting a detailed classification of various security attacks on the control layer. A comprehensive state‐of‐the‐art review of the latest mitigation techniques for various security breaches is also presented. Finally, this paper presents future research directions and challenges for further investigation down the line.
The reflective researcher : Analysing research experiences from doing ethnography in a hospital
- Authors: Heggen, Kristin , Solvoll, Betty-Ann , Engelsrud, Gunn
- Date: 2005
- Type: Text , Journal article
- Relation: Norsk Tidsskrift for sykepleieforskning Vol. 7, no. 2 (2005), p. 3-14
- Full Text: false
- Reviewed:
- Description: A key concept in ethnography is reflectivity. The last decade there has been an increasing discussion about the importance of the reseacher's role in regard to the creation of data as well as the analysis of the data material.
- Description: C1
- Description: 2003001209
Behaviour tracking : using geospatial and behaviour sequence analysis to map crime
- Authors: Keatley, David , Arntfield, Michael , Gill, Paul , Clare, Joe , Oatley, Giles , Bouhana, Noemie , Clarke, David
- Date: 2021
- Type: Text , Journal article
- Relation: Security Journal Vol. 34, no. 1 (2021), p. 184-201
- Full Text: false
- Reviewed:
- Description: Crime is a complex phenomenon. To understand the commission of crime, researchers must map both the temporal and the spatial processes involved. The current research combines a temporal method of analysis, Behaviour Sequence Analysis, with geospatial mapping, to outline a new method of integrating temporal and spatial movements of criminals. To show how the new method can be applied, a burglary scenario was used, and the movements and behaviours of a criminal tracked around the property. Results showed that combining temporal and spatial analyses allows for a clearer account of the process of a crime scene. The current method has application to a large range of other crimes and terrorist movements, for instance between cities and movements within each city. Therefore, the current research provides the foundation framework for a novel method of spatio-temporal analyses of crime. © 2019, Springer Nature Limited.
Accessibility and emotionality of online assessment feedback: Using emoticons to enhance student perceptions of marker competence and warmth
- Authors: Moffitt, Robyn , Padgett, Christine , Grieve, Rachel
- Date: 2020
- Type: Text , Journal article
- Relation: Computers and education Vol. 143, no. (2020), p. 103654
- Full Text: false
- Reviewed:
- Description: Assessment feedback is one of the most powerful learning tools, and in higher education this feedback is increasingly being provided online. The current study investigated the inclusion of emoticons as a method through which to enhance student perceptions of the accessibility and emotionality of written online assessment feedback. Undergraduate students (N = 241) were presented with an online faux essay along with associated written feedback typical of the comments students would receive in the higher education context. The feedback was identical except for the inclusion of emoticons. Using a between-groups design, emoticons were manipulated in two ways: frequency (none, 1, 3, or 6) and valence (happy, sad, or confused). The use of happy emoticons produced significantly higher perceptions of marker warmth when compared to no emoticons, or when negatively valenced emoticons were included. Furthermore, marker competence was significantly higher when 3 happy face emoticons were presented in the feedback than when 3 sad or confused faces were included. Student perceptions of feedback quality and marker professionalism were not affected by emoticon use. Thus, the results suggest that instructors can use positively valenced emoticons to inject some fun, warmth, and emotionality in written online assessment feedback without sacrificing feedback quality or professional integrity. •Experimentally manipulated emoticon valence and frequency in assessment feedback.•Including happy emoticons in feedback increased perceptions of marker warmth.•Marker competence was rated higher with happy than sad or confused face emoticons.•Feedback quality and marker professionalism were unaffected by emoticon inclusion.•Happy face emoticons convey emotionality without compromising feedback quality.
Use of maturity method to estimate early age compressive strength of slab in cold weather
- Authors: Tekle, Biruk , Al‐Deen, Safat , Anwar‐Us‐Saadat, Mohammad , Willans, Njoud , Zhang, Yixia , Lee, Chi King
- Date: 2022
- Type: Text , Journal article
- Relation: Structural concrete : journal of the FIB Vol. 23, no. 2 (2022), p. 1176-1190
- Full Text: false
- Reviewed:
- Description: Accurate estimation of the in situ strength of concrete at early age is very important as it provides the necessary information required to start subsequent construction operations. Overestimation of the strength may cause serious safety hazards and underestimation may lead to unnecessary costly delays. This study investigates the performance of the maturity method in estimating the strength of in situ concrete subjected to cold weather at early age. Instrumented concrete slabs were subjected to cold weather conditions at early ages and their strengths were measured using drilled core samples from the slab. Sensors embedded in the slabs measured the temperature in the concrete which was used to estimate the strength using the maturity method. The measured core strengths at 24 and 72 h after casting are then compared with the estimated strengths using the maturity method and its performance is evaluated. The core strengths are also compared with the strength of standard cylinders cured at the same condition as the slabs. More than 250 cylinders from two slab thicknesses and four batches of concrete were used in the experiments to obtain statistically significant experimental data. The results show that the maturity method performed much better than the standard cylinder strength. On average the standard cylinder strength underestimated the core strength by more than 40% while the maturity method overestimated the strength by less than 10% with a lower variation.