Mechanisms for graph manipulation of transactional performance data are provided in order to identify and emphasize root causes of electronic business system transaction processing performance problems. A method includes receiving a set of data relating to Quality of Service pre-authorization, and conditionally processing subsequent QoS configuration requests based at least in part on the pre-authorization information. Accordingly, preparation time for using content can be reduced. Methods of constructing optical devices and light sources having a bubble-containing substrate are also disclosed. A resistor 115 for limiting the current flowing through the light emitting diode 4 is disposed between an element 114 within the voltage control apparatus 1 for driving the light emitting diode 4 and the input terminal L.