Self-adaptive load-balancing strategy based on a time series pattern for concurrent user access on Web map service

2019 ◽  
Vol 131 ◽  
pp. 60-69 ◽  
Author(s):  
Rui Li ◽  
Guangsheng Dong ◽  
Jie Jiang ◽  
Huayi Wu ◽  
Ning Yang ◽  
...  
Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 439-447
Author(s):  
Lijie Yan ◽  
Xudong Liu

AbstractTo a large extent, the load balancing algorithm affects the clustering performance of the computer. This paper illustrated the common load balancing algorithms and elaborated on the advantages and drawbacks of such algorithms. In addition, this paper provides a kind of balancing algorithm generated on the basis of the load prediction. Due to the dynamic exponential smoothing model, such an algorithm helps obtain the corresponding smoothing coefficient with the server node load time series of current phrase and allows researchers to make prediction with the load value at the next moment of this node. Subsequently, the dispatcher makes the scheduling with the serve request of users according to the load predicted value. OPNET Internet simulated software is applied to the test, and we may conclude from the results that the application of such an algorithm acquires a higher load balancing efficiency and better load balancing effect.


2017 ◽  
pp. 2485-2488
Author(s):  
Christopher D. Michaelis ◽  
Daniel P Ames
Keyword(s):  
Web Map ◽  

The recent progress for spatial resolution of remote sensing imagery led to generate many types of Very HighResolution (VHR) satellite images, consequently, general speaking, it is possible to prepare accurate base map larger than 1:10,000 scale. One of these VHR satellite image is WorldView-3 sensor that launched in August 2014. The resolution of 0.31m makes WorldView-3 the highest resolution commercial satellite in the world. In the current research, a pan-sharpen image from that type, covering an area at Giza Governorate in Egypt, used to determine the suitable large-scale map that could be produced from that image. To reach this objective, two different sources for acquiring Ground Control Points (GCPs). Firstly, very accurate field measurements using GPS and secondly, Web Map Service (WMS) server (in the current research is Google Earth) which is considered a good alternative when GCPs are not available, are used. Accordingly, three scenarios are tested, using the same set of both 16 Ground Control Points (GCPs) as well as 14 Check Points (CHKs), used for evaluation the accuracy of geometric correction of that type of images. First approach using both GCPs and CHKs coordinates acquired by GPS. Second approach using GCPs coordinates acquired by Google Earth and CHKs acquired by GPS. Third approach using GCPs and CHKs coordinates by Google Earth. Results showed that, first approach gives Root Mean Square Error (RMSE) planimeteric discrepancy for GCPs of 0.45m and RMSE planimeteric discrepancy for CHKs of 0.69m. Second approach gives RMSE for GCPs of 1.10m and RMSE for CHKs of 1.75m. Third approach gives RMSE for GCPs of 1.10m and RMSE for CHKs of 1.40m. Taking map accuracy specification of 0.5mm of map scale, the worst values for CHKs points (1.75m&1,4m) resulted from using Google Earth as a source, gives the possibility of producing 1:5000 large-scale map compared with the best value of (0.69m) (map scale 1:2500). This means, for the given parameters of the current research, large scale maps could be produced using Google Earth, in case of GCPs are not available accurately from the field surveying, which is very useful for many users.


2013 ◽  
Vol 21 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Dušan Cibulka

Abstract The paper deals with the performance testing of web mapping services. The paper describes map service tests in which it is possible to determine the performance characteristics of a map service, depending on the location and scale of the map. The implementation of the test is tailored to the Web Map Service specifications provided by the Open Geospatial Consortium. The practical experiment consists of testing the map composition acquired from OpenStreetMap data for the area of southwestern Slovakia. These tests permit checking the performance of services in different positions, verifying the configuration of services, the composition of a map, and the visualization of geodata. The task of this paper is to also highlight the fact that it is not sufficient to only interpret a map service performance with conventional indicators. A map service’s performance should be linked to information about the map’s scale and location.


2010 ◽  
Vol 2 (3) ◽  
pp. 30-47 ◽  
Author(s):  
Michael G. Leahy ◽  
G. Brent Hall

This paper discusses the research-based origins and modular architecture of an open source geospatial tool that facilitates synchronous individual and group discussions using the medium of a Web map service. The software draws on existing open source geospatial projects and associated libraries and techniques that have evolved as part of the new generation of Web applications. The purpose of the software is discussed, highlighting the fusion of existing open source projects to produce new tools. Two case studies are briefly discussed to illustrate the value an open source approach brings to communities who would remain otherwise outside the reach of proprietary software tools. The paper concludes with comments on the project’s future evolution as an open source participatory mapping platform.


2016 ◽  
Vol 164 ◽  
pp. 503-509 ◽  
Author(s):  
Po-Han Chen ◽  
Thanh-Chuong Nguyen
Keyword(s):  
Web Map ◽  

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