Provided is a technique for classifying stocks into business sectors by calculating, for each of multiple exogenous variables, a measure of a tendency for a value of a stock to change as a result of a change in a data value for each such exogenous variable. In an embodiment, a method includes receiving an electronic signal from an accelerometer that represents swallowing activity, extracting at least two features from the signal, classifying the signal as a type of swallowing activity based on the extracted features, and generating an output of the classification. The characteristic of the packet may indicate at least one of a group consisting whether the packet is transmission quality sensitive and whether the packet is transmission throughput sensitive. In some embodiments the sacrificial layer may be configured to survive relatively high temperature processing without substantially affecting the performance of the conversion layer, and to facilitate removal of the substrate via laser lift off. Other components may be detachably added such as a hand grip facilitating freehand shooting with the camera.