scholarly journals Tightness of Invariant Distributions of a Large-scale Flexible Service System Under a Priority Discipline

2012 ◽  
Vol 2 (2) ◽  
pp. 381-408 ◽  
Author(s):  
Alexander L. Stolyar ◽  
Elena Yudovina
Keyword(s):  
Large Scale ◽  
Service System ◽  
Invariant Distributions ◽  
A Priority

scholarly journals Diffusion-Scale Tightness of Invariant Distributions of a Large-Scale Flexible Service System

2015 ◽  
Vol 47 (01) ◽  
pp. 251-269 ◽  
Author(s):  
A. L. Stolyar
Keyword(s):  
Diffusion Process ◽  
Service Time ◽  
Large Scale ◽  
Service System ◽  
Arrival Rate ◽  
Asymptotic Regime ◽  
Invariant Distributions ◽  
Multiple Customer Classes ◽  
The Mean ◽  
Diffusion Scale

A large-scale service system with multiple customer classes and multiple server pools is considered, with the mean service time depending both on the customer class and server pool. The allowed activities (routeing choices) form a tree (in the graph with vertices being both customer classes and server pools). We study the behavior of the system under a leaf activity priority (LAP) policy, introduced by Stolyar and Yudovina (2012). An asymptotic regime is considered, where the arrival rate of customers and number of servers in each pool tend to ∞ in proportion to a scaling parameter r, while the overall system load remains strictly subcritical. We prove tightness of diffusion-scaled (centered at the equilibrium point and scaled down by r −1/2) invariant distributions. As a consequence, we obtain a limit interchange result: the limit of diffusion-scaled invariant distributions is equal to the invariant distribution of the limiting diffusion process.

scholarly journals Diffusion-Scale Tightness of Invariant Distributions of a Large-Scale Flexible Service System

2015 ◽  
Vol 47 (1) ◽  
pp. 251-269 ◽  
Author(s):  
A. L. Stolyar
Keyword(s):  
Diffusion Process ◽  
Service Time ◽  
Large Scale ◽  
Service System ◽  
Arrival Rate ◽  
Asymptotic Regime ◽  
Invariant Distributions ◽  
Multiple Customer Classes ◽  
The Mean ◽  
Diffusion Scale

A large-scale service system with multiple customer classes and multiple server pools is considered, with the mean service time depending both on the customer class and server pool. The allowed activities (routeing choices) form a tree (in the graph with vertices being both customer classes and server pools). We study the behavior of the system under a leaf activity priority (LAP) policy, introduced by Stolyar and Yudovina (2012). An asymptotic regime is considered, where the arrival rate of customers and number of servers in each pool tend to ∞ in proportion to a scaling parameter r, while the overall system load remains strictly subcritical. We prove tightness of diffusion-scaled (centered at the equilibrium point and scaled down by r−1/2) invariant distributions. As a consequence, we obtain a limit interchange result: the limit of diffusion-scaled invariant distributions is equal to the invariant distribution of the limiting diffusion process.

scholarly journals A large-scale service system with packing constraints

2013 ◽  
Vol 41 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Alexander L. Stolyar ◽  
Yuan Zhong
Keyword(s):  
Large Scale ◽  
Service System

Rescue Work and Progress of Analog Seismograms in China

2020 ◽  
Vol 91 (5) ◽  
pp. 2704-2718
Author(s):  
Xuchao Chai ◽  
Qingliang Wang ◽  
Leiyu Mu ◽  
Honglei Wang ◽  
Wenqing Wang ◽  
...  
Keyword(s):  
Large Scale ◽  
Service System ◽  
Distributed Database ◽  
Future Prospects ◽  
Seismic Record ◽  
Rescue Work ◽  
Survey Statistics ◽  
Seismic Records ◽  
China Earthquake ◽  
Funding Support

Abstract Rescue work involving scanning and digitization research on historical analog seismograms nationwide in China was launched in 2017. A series of results have been accomplished. There are more than 13 million analog seismic records existing in China, and about 3 million of them were scanned by December 2019. The Second Monitoring and Application Center of China Earthquake Administration completed the phased construction of the “China Analog Seismic Record Rescue Project” in 2019, which has received a great deal of funding support. Most of the analog seismograms and geophysical records in China will be scanned in the following decade, the corresponding stations and instrument parameters will be also collected during this project to provide retrieval and download service. This article first introduces the survey statistics about scanning and digitalization progress of analog seismic records in China. Second, a management and service system for the storage and query of large scale of seismograms has been established based on distributed database and search engine. Finally, future prospects of the rescue work of analog seismograms are mentioned.

Tidal Flat and Sand Beach Remediation: Choosing Remediation Techniques to Speed Ecological Recovery of Habitats Still Impacted 20 Years after the Gulf War Oil Spill

2014 ◽  
Vol 2014 (1) ◽  
pp. 1719-1733
Author(s):  
Thomas G. Minter ◽  
Jason A. Hale ◽  
Christopher D. Cormack ◽  
Linos Cotsapas ◽  
Jacqueline Michel
Keyword(s):  
Oil Spill ◽  
Large Scale ◽  
Arabian Gulf ◽  
Gulf War ◽  
Tidal Flats ◽  
Suitable Habitat ◽  
Optimal Method ◽  
Sediment Loss ◽  
A Priority ◽  
Ecological Recovery

ABSTRACT After nearly 20 years of limited natural recovery following the Gulf War oil spill, surveys were conducted in 2009-2010 to identify where oil has persisted and ecological recovery has been slow along the Arabian Gulf coastline of Saudi Arabia. In 2011-2013, large-scale remediation projects were executed on 3 locations totaling 155 hectares of tidal flats and sand beaches to speed ecological recovery. Targeted remediation techniques were used as tools to meet the following goals: 1) increase suitable habitat for grazers and burrowing infauna; 2) reduce total petroleum hydrocarbon levels; and 3) improve physical processes (drainage) and reduce associated stressors such as ponding. Three principal techniques were developed and utilized along sheltered and moderately exposed tidal flats: 1) tilling of oiled sediments using tines (rake) or disc harrow attachment, followed by manual removal of remaining surface oil; 2) complete physical removal and disposal of the surface or cohesive subsurface oiling layers; and 3) tilling areas contained within berms while flooded to liberate liquid oil that was subsequently recovered by skimming/vacuuming. The first technique was considered appropriate when there was a well-defined gradient between hardened surface oiling and lightly oiled subsurface sediments, within sandy tidal flats, and where sediment conservation was a priority. This technique resulted in 20% additional oiled surface residue cover, which was removed manually. Resulting sediment loss was minimal. Goals 1, 2 and 3 were met. The second technique was preferred when there was a dry cohesive oiled layer either on the surface or beneath a layer of clean sand and where sediment conservation was not a priority. Excavation of oiled sediments resulted in high sediment loss by physical removal; however, goals 1 and 2 were clearly achieved. Additional re-grading including possible sediment replacement was required to achieve goal 3. The third technique was considered the optimal method when there was a high level of subsurface liquid oiling within tidal flats, and if sediment conservation was a priority. Goal 1 was achieved by breaking up surface barriers. To achieve goals 2 and 3, multiple tilling passes were required to liberate and remove liquid oil. Monitoring results show that while oil levels varied across remediated sites, a trend in reduction was common throughout. Short- and long-term ecological responses are being monitored.

scholarly journals Understanding spatial and temporal patterns of human–elephant conflict in Assam, India

Oryx ◽  
2013 ◽  
Vol 49 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Scott Wilson ◽  
Tammy E. Davies ◽  
Nandita Hazarika ◽  
Alexandra Zimmermann
Keyword(s):  
Large Scale ◽  
Spatial And Temporal Patterns ◽  
Forest Patches ◽  
Small Communities ◽  
Crop Density ◽  
Tea Plantations ◽  
A Priority ◽  
Study Sites ◽  
Conflict Mitigation ◽  
Refuge Areas

AbstractLarge-scale forest encroachment in Assam, India, has led to increasing levels of human–elephant conflict. Conflict mitigation is a priority for the survival of Asian elephants Elephas maximus throughout Asia. We analysed a 3-year dataset of elephant occurrence and related instances of human–elephant conflict, from two sites in Assam, and explored the relationships between the various effects of elephants on human communities and factors influencing the spatial and temporal occurrence of these effects (proximity to water, refuge areas and villages, and human and crop density). The landscapes at both study sites have been transformed by forest loss, with large areas converted to agriculture. Remaining forest patches, which are mostly small, disconnected and degraded, as well as tea plantations, provide refuge areas for elephants as they move through the region. We found that crop depredation and property damage caused by elephants showed well-defined seasonal trends. They also showed a clear diurnal pattern, mostly occurring between 18.00 and 22.00. Small communities within 700 m of a refuge were most affected. In the management of human–elephant conflict in Assam we need to consider the refuge patches used by elephants as they move through the region, the peripheries of which are likely to be conflict hotspots. Small villages on the edges of refuges should be a priority for conflict mitigation assistance, with strategies taking into account seasonal and diurnal variation in elephant behaviour, as well as the socio-economic and cultural composition of communities.

Interrogating the promise of a whole-school approach to intercultural education: An Australian investigation

2018 ◽  
Vol 18 (2) ◽  
pp. 234-247 ◽  
Author(s):  
Sarah Ohi ◽  
Joanne O’Mara ◽  
Ruth Arber ◽  
Catherine Hartung ◽  
Gary Shaw ◽  
...  
Keyword(s):  
Social Constructivism ◽  
Large Scale ◽  
Qualitative Data ◽  
Intercultural Education ◽  
Academic Literature ◽  
Whole School ◽  
Large Scale Study ◽  
The Everyday ◽  
A Priority ◽  
Whole School Approach

Intercultural education (ICE) is a priority for schools and schooling systems worldwide. While extensive policy and academic literature exists that describes how ICE should be done in schools, relatively little has been published about the pragmatics of implementing and enacting ICE, despite evidence that principals, teachers and schools feel ill equipped to teach and engage in ICE. This article investigates how schools implementing ICE are confronted with distinctive challenges. Engaging methodological tools of social constructivism (Denzin and Lincoln, 2005) and an analytical lens supported by social cultural theories of identity and representation (Hall, 1997; Gee, 2004), we argue that the everyday experiences and practices of teachers need be explored, but also interrogated and understood otherwise (Lather, 1991). We draw on qualitative data from a large-scale study conducted in schools in Victoria, Australia. We present three vignettes that elucidate how ICE was enacted at the principal, curriculum and teacher levels. Each vignette is based upon a key challenge confronted by schools and illustrates the processes different schools used to tackle these issues and to embed ICE into the daily schooling practice.

Effective collaboration and governance processes to underpin large-scale natural resource management projects: the Australian Feral Camel Management Project experience

2016 ◽  
Vol 38 (2) ◽  
pp. 117 ◽  
Author(s):  
Quentin Hart ◽  
Andrew Bubb
Keyword(s):  
Resource Management ◽  
Natural Resource Management ◽  
Natural Resource ◽  
Large Scale ◽  
Good Governance ◽  
Operating Environment ◽  
Communication Processes ◽  
Management Project ◽  
A Priority ◽  
Governance Processes

The Australian Feral Camel Management Project involved a large number of diverse formal collaborators and broader stakeholders. Establishing and maintaining formal and informal collaborations was key to the success of the project. Good governance and communication processes underpin such collaboration and support the ability of projects to be flexible and to respond to unexpected changes in operating environment and/or stakeholder concerns. A priority for the project was to establish enduring relationships that would facilitate ongoing feral camel management.

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