Optimal error bound and Fourier regularization for identifying an unknown source in the heat equation

AbstractIn this paper we investigate a problem of the identification of an unknown source from one supplementary temperature measurement at a given instant of time for the transient heat equation. Under an a priori condition we answer the question concerning the best possible accuracy for the problem. The Fourier regularization method is utilized for solving the problem, and its convergent rate is analyzed. Numerical results are presented to illustrate the accuracy and efficiency of the method

AgamottoEye: Recovering Request Flow for Cloud Systems via Log Analysis

Cloud applications are implemented on top of different distributed systems to provide online service. A service request is decomposed into multiple sub-tasks, which are dispatched to different distributed systems components. For cloud providers, monitoring the execution of a service request is crucial to promptly find problems that may compromise cloud availability. In this paper, we present AgamottoEye, to automatically construct request flow from existing logs. AgamottoEye addresses the challenges of analyzing interleaved log instances, and can successfully extract request flow spread across multiple distributed systems. Our experiments with Hadoop2/YARN show that AgamottoEye can analyze 25,050 log instances in 57.4s, and the extracted request flow information is helpful with error detection and diagnosis

Research on Injected Effect and Heat-transfer Characteristics of Narrow-Slit Injection Orifice Used for the Screw Compressor

A narrow-slit injection orifice which is used for the screw compressor injection is described in this paper. Different from the traditional injection orifice, the orifice is slit shaped but not circular. Liquid which is injected by the narrow-slit injection orifice appears as a curtain shape so that the heat transfer area is increased. The cooling effect is enhanced and then the efficiency of the compressor is improved. The injected velocity of the orifice is simulated through the CFD software, and then the experiments are carried out. The study verified the accuracy of the simulation results. It will provide a theoretical foundation for the design of the narrow-slit injection orifice used for the screw compressor