Automated categorization of performance problem diagnosis results

In times of big data and global networking, software performance becomes a major issue in software development. Many enterprise applications were not designed for the current highly frequented usage. Thus, more and more organizations are using Application Performance Monitoring tools, to detect bottlenecks and other performance problems in their product. Meanwhile, there are many different tools on the market which provide a detailed performance-aware analysis of enterprise applications. However the common Application Performance Management tools do not provide any additional automated performance problem diagnosis. The performance expert has to find the cause on its own. diagnoseIT [4], a framework for automatic diagnosis of performance problems in enterprise applications addresses this problem. diagnoseIT extracts performance problem instances from execution traces. The resulting set of problem instances can become huge and the analysis of the problems is very time-consuming. We extend the general concept of diagnoseIT and categorize the resulting set of problem instances into a manageable number of problem categories. Therefore, a concept of categorization is elaborated. We analyze several different categorization approaches and evaluate the performance and the quality of the result. We perform a sensitivity analysis, which analyzes the influence of each attribute of a problem instance on a clustering result. The results of the sensitivity analysis indicates, that there is a potential for optimization. Thus, we introduce a concept of optimization, which optimizes the process of categorization by weighting the attributes and we compare different manual and automatic optimization approaches with regard to the improvement compared to default weights. In the evaluation, we examine the accuracy and the performance of the approaches. The evaluation shows that k-means clustering provides the most promising and best results. Additionally, the evaluation indicates a high potential for optimization. However, the results of the evaluation show that it is difficult to optimize the weights without any knowledge about the analyzed system

A hemispherical acoustic resonator for the measurement of the speed of sound in gases.

A hemispherical acoustic resonator is described which was designed and constructed for the measurement of the speed of sound in gases, at pressures up to 40 MPa and at temperatures in the range from 300 K to 400 K. The hemispherical geometry retains many of the advantages characteristic of the spherical geometry but affords a major advantage at high pressures because one of the transducers may be placed at a position of maximum acoustic density for the radial modes and so loss of signal strength is minimised. A detailed description is given of the resonator and pressure vessel, the thermostat and the various measurement techniques employed. Characterisation of the resonator was achieved using a prototype equatorial plate for which the sound source could be moved over the radius of the cavity. Using the prototype plate, measurements performed in air at room temperature and pressure allowed the transducer configuration to be optimised. Calibration of the resonator was possible by comparison of the values of ula(pj) obtained isothermally in nitrogen with data obtained previously using a spherical resonator. These measurements allowed the resonator's geometry to be characteriseda nd the dependenceo f the radius on temperaturea nd pressuret o be modelled. The semi-empirical model developed using the results of the calibration was tested using measurements obtained in argon; results were obtained simultaneously from the hemispherical resonator and a well-characterised spherical resonator. Measurements on propene together with the results from nitrogen allowed the halfwidths to be modelled and enabled useful information about the loss mechanisms occurring to be extracted from the measured halfwidths. Tetrafluoromethane was subsequently studied and the acoustic virial coefficients and vibrational relaxation times were measured and compared with literature values

Dissonance in Relation to Discrepant Information and Anxiety

This thesis discusses dissonance and its relationship to discrepant information and anxiety

Useful knowledge, 'industrial enlightenment', and the place of India

Research is now turning to the missing place of technology and ‘useful knowledge’ in the debate on the ‘great divergence’ between East and West. Parallel research in the history of science has sought the global dimensions of European knowledge. Joel Mokyr's recent The Enlightened Economy (2009) argued the place of an exceptional ‘industrial enlightenment’ in Europe in explaining industrialization there, but neglected the wide geographic framework of European investigation of the arts and manufactures. This article presents two case studies of European industrial travellers who accessed and described Indian crafts and industries at the time of Britain's industrial revolution and Europe's Enlightenment discourse on crafts and manufactures. The efforts of Anton Hove and Benjamin Heyne to ‘codify’ the ‘tacit’ knowledge of a part of the world distant from Europe were hindered by the English East India Company and the British state. Their accounts, only published much later, provide insight into European perceptions of India's ‘useful knowledge’