QoS-Oriented Grid-Enabled Data Warehouses

Author(s):  
Rogério Luís de Carvalho Costa ◽  
Pedro Furtado

Globally accessible data warehouses are useful in many commercial and scientific organizations. For instance, research centers can be put together through a grid infrastructure in order to form a large virtual organization with a huge virtual data warehouse, which should be transparently and efficiently queried by grid participants. As it is frequent in the grid environment, in the Grid-based Data Warehouse one can both have resource constraints and establish Service Level Objectives (SLOs), providing some Quality of Service (QoS) differentiation for each group of users, participant organizations or requested operations. In this work, we discuss query scheduling and data placement in the grid-based data warehouse, proposing the use of QoS-aware strategies. There are some works on parallel and distributed data warehouses, but most do not concern the grid environment and those which do so, use best-effort oriented strategies. Our experimental results show the importance and effectiveness of proposed strategies.

2011 ◽  
pp. 901-920
Author(s):  
Rogério Luís de Carvalho Costa ◽  
Pedro Furtado

Globally accessible data warehouses are useful in many commercial and scientific organizations. For instance, research centers can be put together through a grid infrastructure in order to form a large virtual organization with a huge virtual data warehouse, which should be transparently and efficiently queried by grid participants. As it is frequent in the grid environment, in the Grid-based Data Warehouse one can both have resource constraints and establish Service Level Objectives (SLOs), providing some Quality of Service (QoS) differentiation for each group of users, participant organizations or requested operations. In this work, we discuss query scheduling and data placement in the grid-based data warehouse, proposing the use of QoS-aware strategies. There are some works on parallel and distributed data warehouses, but most do not concern the grid environment and those which do so, use best-effort oriented strategies. Our experimental results show the importance and effectiveness of proposed strategies.


2012 ◽  
Vol 263-266 ◽  
pp. 1925-1928
Author(s):  
Ren Feng Xu ◽  
Ding Ju Zhu

Grid based data warehouse (GDW) distinguishes itself from other data warehouses based on single computer, parallel computer, cluster, or distributed network due to the characteristics of the grid environment. This article proposes an approach for GDW. GDW approach is good at adapting different hardware platforms and bottom databases by making full exploitation of the heterogeneity and transparency of the grid .


2010 ◽  
pp. 865-886
Author(s):  
Pedro Furtado

Data Warehouses are a crucial technology for current competitive organizations in the globalized world. Size, speed and distributed operation are major challenges concerning those systems. Many data warehouses have huge sizes and the requirement that queries be processed quickly and efficiently, so parallel solutions are deployed to render the necessary efficiency. Distributed operation, on the other hand, concerns global commercial and scientific organizations that need to share their data in a coherent distributed data warehouse. In this article we review the major concepts, systems and research results behind parallel and distributed data warehouses.


Author(s):  
Pedro Furtado

Data Warehouses are a crucial technology for current competitive organizations in the globalized world. Size, speed and distributed operation are major challenges concerning those systems. Many data warehouses have huge sizes and the requirement that queries be processed quickly and efficiently, so parallel solutions are deployed to render the necessary efficiency. Distributed operation, on the other hand, concerns global commercial and scientific organizations that need to share their data in a coherent distributed data warehouse. In this article we review the major concepts, systems and research results behind parallel and distributed data warehouses.


Author(s):  
Maurizio Pighin ◽  
Lucio Ieronutti

Data Warehouses are increasingly used by commercial organizations to extract, from a huge amount of transactional data, concise information useful for supporting decision processes. However, the task of designing a data warehouse and evaluating its effectiveness is not trivial, especially in the case of large databases and in presence of redundant information. The meaning and the quality of selected attributes heavily influence the data warehouse’s effectiveness and the quality of derived decisions. Our research is focused on interactive methodologies and techniques targeted at supporting the data warehouse design and evaluation by taking into account the quality of initial data. In this chapter we propose an approach for supporting the data warehouses development and refinement, providing practical examples and demonstrating the effectiveness of our solution. Our approach is mainly based on two phases: the first one is targeted at interactively guiding the attributes selection by providing quantitative information measuring different statistical and syntactical aspects of data, while the second phase, based on a set of 3D visualizations, gives the opportunity of run-time refining taken design choices according to data examination and analysis. For experimenting proposed solutions on real data, we have developed a tool, called ELDA (EvaLuation DAta warehouse quality), that has been used for supporting the data warehouse design and evaluation.


2016 ◽  
Vol 5 (3) ◽  
pp. 39
Author(s):  
Amegovu K. Andrew

Physical and emotional wellness, as well as access to healthcare, are foundations for successful resettlement. Without feeling healthy, it is difficult to work, to go school, or take care of a family. Many factors can affect refugee health, including geographic origin and refugee camp conditions. Refugees may face a wide variety of acute or chronic health issues (Office of Refugee Resettlement, ORR Annual Report to Congress 2014; http://www.acf.hhs.gov). Resettlement of refugees in Uganda is usually supported by concerted efforts of UNHCR, Governments through the Office of the Prime Minister, OPM with support from host communities, local and international Non-Governmental Organizations. Due to resource constraints and local factors, immigrants are often subjected to poor living conditions which coupled with inadequacy inessential medical supplies might significantly affects quality of care and health service delivery and hence, rendering refugees to poor health status. This study was conducted from 2013-2014 to assess the determinants of health status of Congolese refugees living in Nakivale refugee settlement, in Isingiro district- South Western Uganda. A cross-sectional study design was used involving mixed techniques of both qualitative and quantitative KAP survey. The study focussed on Congolese refugee population in Nakivale Refugee settlement. 2401 key informants’ interviews and 8 focus group discussions respectively were conducted targeting service providers and beneficiaries/Congolese refugees in this case. The data was analysed using SPSS ver.20, 2011. Although majority (97%) of respondents sought medical services from established health facilities, findings confirm a high level of ill health prevalence among Congolese refugees in Nakivale camp, however, the difference in health services and perceived health status in camp versus the one in DRcongo is insignificant ( p=0.000) with respondents perceiving their health status as worse than when they were their own Country before the resettlement. Identified key challenges affecting access & uptake of available health services includes: language barrier; inadequate drugs; and the long distances to access health facilities. The health status of refugees could be improved by addressing the challenges related to language, drug supplies in addition to humanising conditions of shelter, providing appropriate waste disposal facilities while proving adequate food rations and clean & safe drinking water.


OR Spectrum ◽  
2021 ◽  
Author(s):  
Christian Tilk ◽  
Katharina Olkis ◽  
Stefan Irnich

AbstractThe ongoing rise in e-commerce comes along with an increasing number of first-time delivery failures due to the absence of the customer at the delivery location. Failed deliveries result in rework which in turn has a large impact on the carriers’ delivery cost. In the classical vehicle routing problem (VRP) with time windows, each customer request has only one location and one time window describing where and when shipments need to be delivered. In contrast, we introduce and analyze the vehicle routing problem with delivery options (VRPDO), in which some requests can be shipped to alternative locations with possibly different time windows. Furthermore, customers may prefer some delivery options. The carrier must then select, for each request, one delivery option such that the carriers’ overall cost is minimized and a given service level regarding customer preferences is achieved. Moreover, when delivery options share a common location, e.g., a locker, capacities must be respected when assigning shipments. To solve the VRPDO exactly, we present a new branch-price-and-cut algorithm. The associated pricing subproblem is a shortest-path problem with resource constraints that we solve with a bidirectional labeling algorithm on an auxiliary network. We focus on the comparison of two alternative modeling approaches for the auxiliary network and present optimal solutions for instances with up to 100 delivery options. Moreover, we provide 17 new optimal solutions for the benchmark set for the VRP with roaming delivery locations.


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