A Database Performance Evaluation Study: Transaction Model and Simulation System Architecture

2018 ◽  
Vol 16 (1) ◽  
pp. 100-112
Author(s):  
A. N. Rodionov ◽  
◽  
N. V. Eirikh ◽  
O. Ya. Dubey ◽  
◽  
...  
2014 ◽  
Vol 13 (9) ◽  
pp. 4859-4867
Author(s):  
Khaled Saleh Maabreh

Distributed database management systems manage a huge amount of data as well as large and increasingly growing number of users through different types of queries. Therefore, efficient methods for accessing these data volumes will be required to provide a high and an acceptable level of system performance.  Data in these systems are varying in terms of types from texts to images, audios and videos that must be available through an optimized level of replication. Distributed database systems have many parameters like data distribution degree, operation mode and the number of sites and replication. These parameters have played a major role in any performance evaluation study. This paper investigates the main parameters that may affect the system performance, which may help with configuring the distributed database system for enhancing the overall system performance.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Huashan Zhan

In order to improve the accuracy and efficiency of performance evaluation, the interactive application of virtual reality and intelligent big data in landscape design is proposed. Clara algorithm is used to mine the performance evaluation index data of landscape simulation design. The performance evaluation index system of landscape simulation system is established based on the data mined. BP network is used to build a comprehensive evaluation model. The expert scoring method is the evaluation index system scoring, which is used as the input of BP network, and the expected output is a neuron. The value of the neuron represents the comprehensive performance evaluation value of the landscape simulation system. The experimental results show that the evaluation results of the research method are consistent with the expert evaluation results, with high accuracy; with the increasing number of systems, the evaluation efficiency of the research method is faster.


2021 ◽  
Author(s):  
Isabell Wagenhaeuser ◽  
Kerstin Knies ◽  
Vera Rauschenberger ◽  
Michael Eisenmann ◽  
Miriam McDonogh ◽  
...  

Background Antigen rapid diagnostic tests (RDT) for SARS-CoV-2 are fast, broadly available, and inexpensive. Despite this, reliable clinical performance data is sparse. Methods In a prospective performance evaluation study, RDT from three manufacturers (NADAL, Panbio, MEDsan) were compared to quantitative reverse transcription polymerase chain reaction (RT-qPCR) in 5 068 oropharyngeal swabs for detection of SARS-CoV-2 in a hospital setting. Viral load was derived from standardized RT-qPCR Cycle threshold (Ct) values. The data collection period ranged from November 12, 2020 to February 28, 2021. Findings Overall, sensitivity of RDT compared to RT-qPCR was 42.57% (95% CI 33.38%-52.31%), and specificity 99.68% (95% CI 99.48%-99.80%). Sensitivity declined with decreasing viral load from 100% in samples with a deduced viral load of 10^8 SARS-CoV-2 RNA copies per ml to 8.82% in samples with a viral load lower than 104 SARS-CoV-2 RNA copies per ml. No significant differences in sensitivity or specificity could be observed between the three manufacturers, or between samples with and without spike protein variant B.1.1.7. The NPV in the study cohort was 98.84%; the PPV in persons with typical COVID-19 symptoms was 97.37%, and 28.57% in persons without or with atypical symptoms. Interpretation RDT are a reliable method to diagnose SARS-CoV-2 infection in persons with high viral load. RDT are a valuable addition to RT-qPCR testing, as they reliably detect infectious persons with high viral loads before RT-qPCR results are available. Funding German Federal Ministry for Education and Science (BMBF), Free State of Bavaria


2014 ◽  
Vol 543-547 ◽  
pp. 3402-3405
Author(s):  
Ling Lu

The design and realization of virtual simulation environment for non-lethal weapon system is presented. Besides the system architecture and design conception, several key problems and our solutions when developing a virtual simulation system, such as OpenGL based on dynamic geometry modeling, scene organization, and interaction are discussed.


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