Advanced rockfall modelling for risk mitigation: tree impact and fragmentation

2021 ◽  
Author(s):  
Camilla Lanfranconi ◽  
Paolo Frattini ◽  
Giovanni Battista Crosta ◽  
Gianluca Sala ◽  
Davide Bertolo ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Case Studies ◽  
Risk Mitigation ◽  
Cost Effective ◽  
Protective Role ◽  
Main Body ◽  
Forest Density ◽  
3D Numerical Modelling

<p>Despite their centrality to rockfall risk management, two issues are frequently overlooked: the role of forests in rockfall dynamic and the fragmentation phenomenon. To investigate the importance of these issues we have developed advanced modelling case studies in two representative sites that have been recently affected by rockfall events in the Aosta Valley Region (Western Italian Alps). In the Saint Oyen case study, about 17,500 m3 of rock detached in March 2019 and reached a service road and the sport center in the lower part of the slope, passing through a mature fir forest. The presence of the forest has significantly influenced the rocks distribution along the slope, increasing the lateral dispersion of trajectories and reducing the mobility. For the design of defensive works, 3D rockfall models of three future potential risk scenarios were therefore performed by using the tree-impact algorithm of the code HY-STONE (Frattini et al., 2012). This algorithm provides the location of impacts on trees, the absorbed energy, and the deviation angle. The input parameters (i.e., the value of diameter at breast height and the forest density) were based on direct measurements of the fir forest. Compared with a traditional simulation without the protective role of forests, the results of 3D numerical modelling with tree-impact algorithm show a decrease in the number of blocks impacting the barriers (91%), no variations in the bouncing heights (for 95<sup>th</sup> percentile), and an increase in the kinetic energies due to a filter effect by the forest (85% for 95<sup>th</sup> percentile). In the Roisan case study, about 1,050 m3 of rock toppled in October 2019. While the main body of the rockfall stopped in a relatively flat area close to the failure, two blocks were exceptionally able to reach the foot of the slope causing the interruption of a municipal road. An attempt to back-calibrate this event with HY-STONE showed difficulties to describe the behaviour of these isolated blocks with respects to the main landslide body. A possible explanation for this behaviour is that the detached volume fragmented soon after impacting the slope, giving rise to flying fragments with higher mobility. To test this hypothesis we accounted for fragmentation through a specific algorithm of HY-STONE that fragments the falling blocks when their energy overcomes a certain threshold and simulate the behaviour of the resulting fragments. This approach allowed to accurately replicate the rockfall event. We therefore adopted this approach for defensive-works design, simulating all the unstable volumes overhanging the municipal road. Compared with a traditional simulation, the results of 3D numerical modelling with fragmentation algorithm show an increase in the number of blocks impacting the barriers (86%) and in the bouncing heights (96% for 95<sup>th</sup> percentile), with a decrease of the kinetic energy due to comminution (39% for 95<sup>th</sup> percentile). These two case studies demonstrate the importance of accounting for the forest or for fragmentation in the design of cost-effective defensive works.</p><p> </p><p>Frattini P, Crosta GB, Agliardi F (2012) Rockfall characterization and modeling. Landslides: types, mechanisms and modelling 22:267-281</p>

scholarly journals Can We Generalize from Case Studies?

2015 ◽  
Vol 15 (3) ◽  
pp. 152-175 ◽  
Author(s):  
Paul F. Steinberg
Keyword(s):  
Case Studies ◽  
Single Case ◽  
Case Study Research ◽  
Political Systems ◽  
Ceteris Paribus ◽  
Large N ◽  
Climate Change Politics ◽  
The Comparative Study

This article considers the role of generalization in comparative case studies, using as exemplars the contributions to this special issue on climate change politics. As a research practice, generalization is a logical argument for extending one’s claims beyond the data, positing a connection between events that were studied and those that were not. No methodological tradition is exempt from the requirement to demonstrate a compelling logic of generalization. The article presents a taxonomy of the logics of generalization underlying diverse research methodologies, which often go unstated and unexamined. I introduce the concept of resonance groups, which provide a causeway for cross-system generalization from single case studies. Overall the results suggest that in the comparative study of complex political systems, case study research is, ceteris paribus, on par with large-N research with respect to generalizability.

Quantitative Selection of Variation Reduction Plans

1998 ◽  
Author(s):  
Anna C. Thornton
Keyword(s):  
Risk Mitigation ◽  
Cost Effective ◽  
Variation Reduction ◽  
Multiple Quality Characteristics ◽  
Cost Effective Approach ◽  
Manufacturing Performance ◽  
The Impact ◽  
Manufacturing Variation ◽  
Selection Of

Abstract Quality has been a rallying call in the design and manufacturing world for the last two decades. One way to improve quality is to reduce the impact of manufacturing variation. Variation risk mitigation is challenging especially when a product has multiple quality characteristics and complex production and assembly. It is common wisdom that companies should identify and mitigate the risk associated with variation throughout the design process. As yield problems are identified, they should be mitigated using the most cost effective approach. One approach to variation risk mitigation is variation reduction (VR). VR targets reduction of variation introduced by existing manufacturing processes using tools such as Design of Experiments (DOE) and robust design. Many companies have specialized groups that specialize in these methods. VR teams have the role of improving manufacturing performance; however, these teams are limited in their resources. In addition, no tools exist to quantitatively determine where a VR team’s efforts are most effectively deployed. This paper provides a mathematical and optimization model to best allocate VR resources in a complex product.

scholarly journals Charity flea markets – an amalgamation of product philanthropy and volunteering

2020 ◽  
Vol 17 (2) ◽  
pp. 203-224
Author(s):  
Sandra Stötzer ◽  
René C. Andeßner ◽  
Sarah Scheichl
Keyword(s):  
Resource Management ◽  
Case Studies ◽  
Case Study Approach ◽  
Study Approach ◽  
Unique Event ◽  
Flea Markets ◽  
Flea Market

AbstractThis paper offers one of the first efforts at exploring the role of charity flea markets as a fundraising practice used by nonprofits to mobilize various resources like individual and corporate in-kind giving and volunteering in an unique event setting. With the support of volunteers, nonprofits generate cash by reselling product donations and by catering. As an innovative contribution to the so far limited research on flea markets and in-kind giving, our study uses an explorative case study approach based on guided interviews with Austrian flea market operators. The purpose of the case studies is to examine the specifics, benefits, challenges, and prospects of this underexplored funding instrument. Our findings contribute to an enhanced understanding of both charity flea markets and nonprofits̕ resource management and can assist charities in processing in-kind donations effectively and sustainably.

scholarly journals Case study of ozone anomalies over northern Russia in the 2015/2016 winter: measurements and numerical modelling

2018 ◽  
Vol 36 (6) ◽  
pp. 1495-1505 ◽  
Author(s):  
Yury M. Timofeyev ◽  
Sergei P. Smyshlyaev ◽  
Yana A. Virolainen ◽  
Alexander S. Garkusha ◽  
Alexander V. Polyakov ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Three Dimensional ◽  
The Arctic ◽  
Atmospheric Models ◽  
Remote Sensing Techniques ◽  
Infrared Fourier Spectrometer ◽  
Northern Russia ◽  
Stratospheric Clouds

Abstract. Episodes of extremely low ozone columns were observed over the territory of Russia in the Arctic winter of 2015/2016 and the beginning of spring 2016. We compare total ozone columns (TOCs) from different remote sensing techniques (satellite and ground-based observations) with results of numerical modelling over the territory of the Urals and Siberia for this period. We demonstrate that the provided monitoring systems (including the new Russian Infrared Fourier Spectrometer IKFS-2) and modern three-dimensional atmospheric models can capture the observed TOC anomalies. However, the results of observations and modelling show differences of up to 20 %–30 % in TOC measurements. Analysis of the role of chemical and dynamical processes demonstrates that the observed short-term TOC variability is not a result of local photochemical loss initiated by heterogeneous halogen activation on particles of polar stratospheric clouds that formed under low temperatures in the mid-winter.

scholarly journals Case study research for better evaluations of complex interventions: rationale and challenges

BMC Medicine ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Sara Paparini ◽  
Judith Green ◽  
Chrysanthi Papoutsi ◽  
Jamie Murdoch ◽  
Mark Petticrew ◽  
...  
Keyword(s):  
Public Health ◽  
Health Services ◽  
Case Studies ◽  
Health Research ◽  
Case Study Research ◽  
Main Body ◽  
Case Study Methodology ◽  
Study Research ◽  
Empirical Case Studies

Abstract Background The need for better methods for evaluation in health research has been widely recognised. The ‘complexity turn’ has drawn attention to the limitations of relying on causal inference from randomised controlled trials alone for understanding whether, and under which conditions, interventions in complex systems improve health services or the public health, and what mechanisms might link interventions and outcomes. We argue that case study research—currently denigrated as poor evidence—is an under-utilised resource for not only providing evidence about context and transferability, but also for helping strengthen causal inferences when pathways between intervention and effects are likely to be non-linear. Main body Case study research, as an overall approach, is based on in-depth explorations of complex phenomena in their natural, or real-life, settings. Empirical case studies typically enable dynamic understanding of complex challenges and provide evidence about causal mechanisms and the necessary and sufficient conditions (contexts) for intervention implementation and effects. This is essential evidence not just for researchers concerned about internal and external validity, but also research users in policy and practice who need to know what the likely effects of complex programmes or interventions will be in their settings. The health sciences have much to learn from scholarship on case study methodology in the social sciences. However, there are multiple challenges in fully exploiting the potential learning from case study research. First are misconceptions that case study research can only provide exploratory or descriptive evidence. Second, there is little consensus about what a case study is, and considerable diversity in how empirical case studies are conducted and reported. Finally, as case study researchers typically (and appropriately) focus on thick description (that captures contextual detail), it can be challenging to identify the key messages related to intervention evaluation from case study reports. Conclusion Whilst the diversity of published case studies in health services and public health research is rich and productive, we recommend further clarity and specific methodological guidance for those reporting case study research for evaluation audiences.

Contemporary Mythopoiesis: the role of Herodotus in Neil Gaiman’s American Gods

2020 ◽  
Vol 12 (3) ◽  
pp. 299-322
Author(s):  
Vanda Zajko
Keyword(s):  
Political Power ◽  
Interesting Case ◽  
Cultural Relativism ◽  
Main Body ◽  
Television Series ◽  
Ancient Greek ◽  
Cultural Form ◽  
Different Cultures

Abstract This article explores Neil Gaiman’s transmedial work American Gods as an example of contemporary mythmaking. Published in novel form in 2001 and launched as a television series in 2017, American Gods provides a commentary on the connectedness between different systems of stories and on myth itself as a vital present-day cultural form. It also provides us with a model for repurposing ancient material without reproducing the traditional hierarchies associated with cultures of storytelling. Gaiman’s text is an interesting case-study from the perspective of classical reception because he sidelines the ancient Greek gods in the main body of his story, while simultaneously positioning the ancient historian Herodotus as a significant intertext. The process of evaluating different cultures often veers between analyses which focus on similarities manifested across place and time and those which espouse a form of cultural relativism, a ‘live and let live’ philosophy. Gaiman seems to be offering something else here, namely a more vital and connected model for co-existence, one which is moving towards a pluri-versal perspective that acknowledges the links between political power, knowledge, and identity.

Examining the mediating role of learning engagement, learning process and learning experience on the learning outcomes through localized real case studies

2014 ◽  
Vol 56 (4) ◽  
pp. 287-302 ◽  
Author(s):  
Mathews Nkhoma ◽  
Narumon Sriratanaviriyakul ◽  
Hiep Pham Cong ◽  
Tri Khai Lam
Keyword(s):  
Learning Outcomes ◽  
Case Studies ◽  
Undergraduate Students ◽  
Learning Process ◽  
Learning Experience ◽  
Learning Engagement ◽  
Content Type ◽  
Mediating Role

Purpose – The purpose of this paper is to understand the impact of real, localized case studies on students’ learning engagement, the learning process and learning experience and the role of such case studies in influencing students’ learning outcomes. Design/methodology/approach – Data were collected from 400 undergraduate students through an online questionnaire immediately after discussion of the case in Business Information Systems classes. Student learning from the case study was measured by two components consisting of case knowledge and case perceptions. The student course engagement questionnaire was used to examine engagement in skills, emotions, participation and performance while the study process questionnaire was administered to assess students’ learning approaches. Additionally, the seven predominant roles of the feedback were used to analyse students’ learning experience. Finally, students’ learning outcomes were assessed both in group performance and individual performance. Structure equation modelling was applied to test the causal model. Findings – The results revealed that the case study had a positive influence on students’ engagement in skills and emotions. Moreover, case perceptions led students to surface approach in their learning. Furthermore, case knowledge had a positive impact on the learning experience. Research limitations/implications – The study suggests that localized case studies should be designed cautiously. Furthermore the method of instruction regarding the method must be clearly explained for undergraduate students. Future research should consider a way of evaluating academic achievement as a result of using localized cases. Originality/value – The findings reported in the paper contributed to an area of educational research by emphasizing on the mediating role of learning engagement, the learning process and the learning experience.

3D numerical modelling of graben interaction and linkage: a case study of the Canyonlands grabens, Utah

2013 ◽  
Vol 25 (4) ◽  
pp. 436-449 ◽  
Author(s):  
Vaneeda Allken ◽  
Ritske S. Huismans ◽  
Haakon Fossen ◽  
Cedric Thieulot
Keyword(s):  
Numerical Modelling ◽  
3D Numerical Modelling

scholarly journals Assessing the Process of Knowledge Transfer — An Empirical Study

2009 ◽  
Vol 08 (03) ◽  
pp. 251-265 ◽  
Author(s):  
Champika Liyanage ◽  
Tabarak Ballal ◽  
Taha Elhag
Keyword(s):  
Knowledge Transfer ◽  
Case Studies ◽  
Construction Projects ◽  
Private Finance Initiative ◽  
Business Environments ◽  
Organisational Knowledge ◽  
The Uk ◽  
Competitive Nature

This paper investigates and evaluates the process of knowledge transfer in construction projects. Due to the highly competitive nature of business environments, knowledge transfer between organisations has become increasingly popular in recent years. However, although organisations can realise remarkable benefits by transferring knowledge from one unit to another, successful knowledge transfer can be difficult to achieve. The discussions presented in the paper are mainly based on findings of two case studies. The two cases were selected from Private Finance Initiative (PFI) projects in the UK. According to the case study findings, different stages of a knowledge transfer process can be overlapped, omitted, repeated as well as intermitted and then restarted. One of the significant findings of the case studies was the role of the "knowledge mediator". In selected case studies, there were external consultants and expert staff in the form of knowledge mediators. The importance of their roles was frequently highlighted by the interview participants. They were not only facilitating the close liaison between the knowledge source and the receiver, but also their role was strongly associated with practices of translation and interpretation. This combined role of mediator/translator, therefore, appears to be particularly significant for inter-organisational knowledge transfer in PFI projects.

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