Shock waves emission after collapse of a laser-induced bubble in the liquid was studied experimentally by using a PTZ hydrophone. An experimental method and a Cavitation detection system was designed to investigate bubble collapse noise in this article. When a focused short laser pulse was focused in a liquid near a solid wall, it induced optical breakdown, the emission of shock waves and the generation of cavitation bubbles. A PZT hydrophone was used to detect the shock wave emitted during bubble oscillations. In addition, a software based on MATLAB was designed for analyzing cavitation noise. The software system had multiple functionalities, namely signal reading, noise reduction, signal analysis in frequency domain, and display. The results showed that the software can not only reflect the spectral characteristics of the noise quickly but also can interpret the current cavitation station according to the changing rules of different cavitation station. The results of the research have strong implications for cavitation phenomena analysis and cavitation warning systems in turbines, propellers, and other irrigation machinery.
Cloud Computing has become more and more prevalent over the past few years, and we have seen the importance of
Infrastructure-as-a-service (IaaS). This kind of service enables scaling of bandwidth, memory, computing power and
storage. But the SLA in IaaS also faces complexity and variety. Users also consider the business of the service. To meet
the most users requirements, a methodology for designing optimal SLA in IaaS from the business perspectives is
proposed. This method is different from the conventional SLA design method, It not only focuses on service provider
perspective, also from the customer to carry on the design. This methodology better captures the linkage between service
provider and service client by considering minimizing the business loss originated from performance degradation and IT
infrastructure failures and maximizing profits for service provider and clients. An optimal design in an IaaS model is
provided and an example are analyzed to show this approach obtain higher profit.