Designing topology-aware collective communication algorithms for large scale InfiniBand clusters: Case studies with Scatter and Gather

2010 ◽  
Author(s):  
Krishna Kandalla ◽  
Hari Subramoni ◽  
Abhinav Vishnu ◽  
Dhabaleswar K. Panda
Keyword(s):  
Case Studies ◽  
Large Scale ◽  
Collective Communication ◽  
Communication Algorithms ◽  
Infiniband Clusters

scholarly journals Modeling regional impacts and resilience to water service disruptions in urban economies

2021 ◽  
pp. 239980832199870
Author(s):  
Sheree A Pagsuyoin ◽  
Joost R Santos
Keyword(s):  
Case Studies ◽  
Large Scale ◽  
Urban Region ◽  
Economic Losses ◽  
Drought Severity ◽  
Severe Drought ◽  
Time Varying ◽  
National Capital Region ◽  
Economic Sectors ◽  
The Impact

Water is a critical natural resource that sustains the productivity of many economic sectors, whether directly or indirectly. Climate change alongside rapid growth and development are a threat to water sustainability and regional productivity. In this paper, we develop an extension to the economic input-output model to assess the impact of water supply disruptions to regional economies. The model utilizes the inoperability variable, which measures the extent to which an infrastructure system or economic sector is unable to deliver its intended output. While the inoperability concept has been utilized in previous applications, this paper offers extensions that capture the time-varying nature of inoperability as the sectors recover from a disruptive event, such as drought. The model extension is capable of inserting inoperability adjustments within the drought timeline to capture time-varying likelihoods and severities, as well as the dependencies of various economic sectors on water. The model was applied to case studies of severe drought in two regions: (1) the state of Massachusetts (MA) and (2) the US National Capital Region (NCR). These regions were selected to contrast drought resilience between a mixed urban–rural region (MA) and a highly urban region (NCR). These regions also have comparable overall gross domestic products despite significant differences in the distribution and share of the economic sectors comprising each region. The results of the case studies indicate that in both regions, the utility and real estate sectors suffer the largest economic loss; nonetheless, results also identify region-specific sectors that incur significant losses. For the NCR, three sectors in the top 10 ranking of highest economic losses are government-related, whereas in the MA, four sectors in the top 10 are manufacturing sectors. Furthermore, the accommodation sector has also been included in the NCR case intuitively because of the high concentration of museums and famous landmarks. In contrast, the Wholesale Trade sector was among the sectors with the highest economic losses in the MA case study because of its large geographic size conducive for warehouses used as nodes for large-scale supply chain networks. Future modeling extensions could potentially include analysis of water demand and supply management strategies that can enhance regional resilience against droughts. Other regional case studies can also be pursued in future efforts to analyze various categories of drought severity beyond the case studies featured in this paper.

scholarly journals Exploiting Proximity-Based Mobile Apps for Large-Scale Location Privacy Probing

2018 ◽  
Vol 2018 ◽  
pp. 1-22 ◽  
Author(s):  
Shuang Zhao ◽  
Xiapu Luo ◽  
Xiaobo Ma ◽  
Bo Bai ◽  
Yankang Zhao ◽  
...  
Keyword(s):  
Social Networks ◽  
Case Studies ◽  
Real World ◽  
Emission Reduction ◽  
Large Scale ◽  
Location Privacy ◽  
Mobile Apps ◽  
Physical World ◽  
Typical Type ◽  
Location Spoofing

Proximity-based apps have been changing the way people interact with each other in the physical world. To help people extend their social networks, proximity-based nearby-stranger (NS) apps that encourage people to make friends with nearby strangers have gained popularity recently. As another typical type of proximity-based apps, some ridesharing (RS) apps allowing drivers to search nearby passengers and get their ridesharing requests also become popular due to their contribution to economy and emission reduction. In this paper, we concentrate on the location privacy of proximity-based mobile apps. By analyzing the communication mechanism, we find that many apps of this type are vulnerable to large-scale location spoofing attack (LLSA). We accordingly propose three approaches to performing LLSA. To evaluate the threat of LLSA posed to proximity-based mobile apps, we perform real-world case studies against an NS app named Weibo and an RS app called Didi. The results show that our approaches can effectively and automatically collect a huge volume of users’ locations or travel records, thereby demonstrating the severity of LLSA. We apply the LLSA approaches against nine popular proximity-based apps with millions of installations to evaluate the defense strength. We finally suggest possible countermeasures for the proposed attacks.

Drama and Environment: Joining Forces to Engage Children and Young People in Environmental Education

2013 ◽  
Vol 29 (2) ◽  
pp. 182-201 ◽  
Author(s):  
David J. Curtis ◽  
Mark Howden ◽  
Fran Curtis ◽  
Ian McColm ◽  
Juliet Scrine ◽  
...  
Keyword(s):  
Environmental Education ◽  
Case Studies ◽  
Large Scale ◽  
Environmental Issues ◽  
Contemporary Society ◽  
Children And Young People ◽  
School Based ◽  
Qualitative Evidence ◽  
Theatre Company ◽  
Theatre In Education

AbstractEngaging and exciting students about the environment remains a challenge in contemporary society, even while objective measures show the rapid state of the world's environment declining. To illuminate the integration of drama and environmental education as a means of engaging students in environmental issues, the work of performance companies Evergreen Theatre, Leapfish and Eaton Gorge Theatre Company, the ecological oratorio Plague and the Moonflower, and a school-based trial of play-building were examined through survey data and participant observations. These case studies employed drama in different ways — theatre-in-education, play-building, and large-scale performance event. The four case studies provide quantitative and qualitative evidence for drama-based activities leading to an improvement in knowledge about the environment and understandings about the consequences of one's actions. In observing and participating in these case studies, we reflect that drama is a means of synthesising and presenting scientific research in ways that are creative and multi-layered, and which excite students, helping maintain their attention and facilitating their engagement.

scholarly journals Coupling between Large-Scale Atmospheric Processes and Mesoscale Land–Atmosphere Interactions in the U.S. Southern Great Plains during Summer. Part II: Mean Impacts of the Mesoscale

2004 ◽  
Vol 5 (6) ◽  
pp. 1247-1258 ◽  
Author(s):  
Christopher P. Weaver
Keyword(s):  
Case Studies ◽  
Time Scales ◽  
Great Plains ◽  
Large Scale ◽  
Spatial Scales ◽  
Surface Heterogeneity ◽  
Atmospheric Modeling ◽  
Mesoscale Circulations ◽  
Southern Great Plains ◽  
Atmospheric Processes

Abstract This is Part II of a two-part study of mesoscale land–atmosphere interactions in the summertime U.S. Southern Great Plains. Part I focused on case studies drawn from monthlong (July 1995–97), high-resolution Regional Atmospheric Modeling System (RAMS) simulations carried out to investigate these interactions. These case studies were chosen to highlight key features of the lower-tropospheric mesoscale circulations that frequently arise in this region and season due to mesoscale heterogeneity in the surface fluxes. In this paper, Part II, the RAMS-simulated mesoscale dynamical processes described in the Part I case studies are examined from a domain-averaged perspective to assess their importance in the overall regional hydrometeorology. The spatial statistics of key simulated mesoscale variables—for example, vertical velocity and the vertical flux of water vapor—are quantified here. Composite averages of the mesoscale and large-scale-mean variables over different meteorological or dynamical regimes are also calculated. The main finding is that, during dry periods, or similarly, during periods characterized by large-scale-mean subsidence, the characteristic signature of surface-heterogeneity-forced mesoscale circulations, including enhanced vertical motion variability and enhanced mesoscale fluxes in the lowest few kilometers of the atmosphere, consistently emerges. Furthermore, the impact of these mesoscale circulations is nonnegligible compared to the large-scale dynamics at domain-averaged (200 km × 200 km) spatial scales and weekly to monthly time scales. These findings support the hypothesis that the land– atmosphere interactions associated with mesoscale surface heterogeneity can provide pathways whereby diurnal, mesoscale atmospheric processes can scale up to have more general impacts at larger spatial scales and over longer time scales.

Majority Quantification and Quantity Superlatives

2021 ◽  
Author(s):  
Carmen Dobrovie-Sorin ◽  
Ion Giurgea
Keyword(s):  
Case Studies ◽  
Large Scale ◽  
Linguistic Theory ◽  
Number Marking ◽  
Semantic Types

This book is a study of the syntax and semantics of proportional Most and other majority quantifiers across languages. Based on data drawn from around forty languages, this book reveals the existence of two semantic types of Most: a distributive type, which compares cardinalities of sets of atoms, and a “cumulative” type, which involves measuring plural and mass entities with respect to a whole. On the syntactic side, the most important difference is between non-partitive and partitive configurations. Certain majority quantifiers are specialized for partitive constructions, others are also allowed in non-partitives. We also examine complex majority expressions of the type The Largest Part and nominal quantifiers of the type The Majority. This large scale crosslinguistic investigation qualifies as a piece of typological research that moreover offers several case studies on both well-studied and less investigated languages (English, German, Icelandic, Romanian, Italian, Hungarian, Basque, Latin, Hindi, Syrian Arabic). The proposed analyses raise new theoretical questions regarding issues such as number marking, partitivity, kind reference, (in)definiteness marking, which are crucial issues for linguistic theory. Noteworthy is the attention paid to mass and collective quantification, an under-studied area. We argue in favor of a quantificational analysis of Most, against recent analyses that attempt to derive the proportional interpretation from the superlative, but we adopt a bipartition-cum-superlative analysis for The Largest Part.

A systematic review of life cycle assessment of hydrogen for road transport use

2021 ◽  
Author(s):  
Dyah Ika Rinawati ◽  
Alexander Ryota Keeley ◽  
Shutaro Takeda ◽  
Shunsuke Managi
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Hydrogen Production ◽  
Case Studies ◽  
Large Scale ◽  
Road Transport ◽  
Fuel Cell Vehicle ◽  
Intergovernmental Panel ◽  
Hybrid Lca ◽  
Complete Life Cycle

Abstract This study conducted a systematic literature review of the technical aspects and methodological choices in life cycle assessment (LCA) studies of using hydrogen for road transport. More than 70 scientific papers published during 2000–2021 were reviewed, in which more than 350 case studies of use of hydrogen in the automotive sector were found. Only some studies used hybrid LCA and energetic input-output LCA, whereas most studies addressed attributional process-based LCA. A categorization based on the life cycle scope distinguished case studies that addressed the well-to-tank (WTT), well-to-wheel (WTW), and complete life cycle approaches. Furthermore, based on the hydrogen production process, these case studies were classified into four categories: thermochemical, electrochemical, thermal-electrochemical, and biochemical. Moreover, based on the hydrogen production site, the case studies were classified as centralized, on-site, and on-board. The fuel cell vehicle passenger car was the most commonly used vehicle. The functional unit for the WTT studies was mostly mass or energy, and vehicle distance for the WTW and complete life cycle studies. Global warming potential (GWP) and energy consumption were the most influential categories. Apart from the GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model and the Intergovernmental Panel on Climate Change for assessing the GWP, the Centrum voor Milieukunde Leiden method was most widely used in other impact categories. Most of the articles under review were comparative LCA studies on different hydrogen pathways and powertrains. The findings provide baseline data not only for large-scale applications, but also for improving the efficiency of hydrogen use in road transport.

Study of sand wave migration over five years as observed in two windfarm development areas, and the implications for building on moving substrates in the North Sea

2014 ◽  
Vol 105 (4) ◽  
pp. 241-249 ◽  
Author(s):  
Ken P. Games ◽  
David I. Gordon
Keyword(s):  
Case Studies ◽  
Large Scale ◽  
Oil And Gas ◽  
Sand Wave ◽  
Sand Waves ◽  
Migration Rates ◽  
The North ◽  
The North Sea ◽  
Wave Migration ◽  
The Impact

ABSTRACTSand waves are well known indicators of a mobile seabed. What do we expect of these features in terms of migration rates and seabed scour? We discuss these effects on seabed structures, both for the Oil and Gas and the Windfarm Industries, and consider how these impact on turbines and buried cables. Two case studies are presented. The first concerns a windfarm with a five-year gap between the planning survey and a subsequent cable route and environmental assessment survey. This revealed large-scale movements of sand waves, with the displacement of an isolated feature of 155 m in five years. Secondly, another windfarm development involved a re-survey, again over a five-year period, but after the turbines had been installed. This showed movements of sand waves of ∼50 m in five years. Observations of the scour effects on the turbines are discussed. Both sites revealed the presence of barchans. Whilst these have been extensively studied on land, there are few examples of how they behave in the marine environment. The two case studies presented show that mass transport is potentially much greater than expected and that this has implications for choosing turbine locations, the effect of scour, and the impact these sediment movements are likely to have on power cables.

Could lean and green be the driver to integrate business improvement throughout the organisation?

2018 ◽  
Vol 67 (1) ◽  
pp. 207-219 ◽  
Author(s):  
Lara Chaplin ◽  
Simon T.J. O’Rourke
Keyword(s):  
Case Studies ◽  
Large Scale ◽  
Participant Observation ◽  
Integrated Approach ◽  
Thick Description ◽  
Content Type ◽  
Main Research ◽  
Lean And Green ◽  
Multiple Case ◽  
Multiple Case Studies

Purpose It seems to be the consensus (Zhang et al., 2012; George et al., 2003; Arumugam et al., 2013) that Lean Six Sigma (LSS) has become a beneficial improvement initiative used in a variety of industries. There is a move towards integrating any high-level business improvement methods holistically throughout the whole organisation. Indeed, Hoerl (2014) explored the idea that when using LSS for business improvement, the programme should engage the whole organisation in much the same way as the financial function is present throughout each department. The purpose of this paper is to posit that using the lean and green agenda may be the driver to achieve integration. Design/methodology/approach The research adopted a subjective ontological perspective with the researcher using participant observation as the main research instrument. Denzin and Lincoln (2005) note that it is now common for scholars to argue that the only relevant data are those based upon the personal experience of the researcher; this served as an informing foundation for the approach for the exploration of the topic. Based on multiple case studies, chosen because they operate in different sectors, the paper adopted an extended case method (Burawoy, 1998) to analyse and gather the research. The organisations were chosen because they both were at a similar stage in their continuous improvement (CI) journey. The main reasoning behind the selection of the two different organisations is to reach “Thick Description” (Geertz, 1973, p. 3, 2001). Findings The findings suggest that there are still significant benefits of implementing a large-scale lean agenda in particular when using an LSS methodology. The paper finds that there are also significant gaps in achieving full integration within the organisation and argues that lean and CI are still the remit of the operations manager. The document goes on to argue that if the CI initiative is driven by the corporate social responsibility (CSR) plan, then any lean/lean green implementation will enable the company to drive CI integration with all stakeholders. Research limitations/implications The research has implications for those responsible for the CSR function within the organisation and the operations manager who is charged with implementing any lean/lean and green CI. Practical implications The paper argues that the lean and green agenda can drive integration of any CI activity throughout the organisation and suggests that the way this can be achieved is any CI activity that is included in the wider CSR plan. Social implications This paper contributes to the “lean and green” agenda and offers a solution for the problem of integrating LSS activities throughout the whole organisation by placing CI and LSS within the CSR remit. Originality/value There is little consensus how this holistic integrated approach should be implemented by the company. This research uses multiple case studies to critically examine the application of LSS as an improvement programme within two large UK-based organisations, each company operating in very different industry sectors to identify the benefits of LSS but also the missed “green/societal” opportunities and argues that if any lean and lean and green agenda is to be holistically adopted, then any CI activity should be driven by the CSR department.

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