The present disclosure provides a memory cell. For example, the mixed amount of the thermoplastic resin or thermosetting resin is preferably equal to or lower than two times the amount of the conjugated organic semiconductor polymer, and a conjugated organic semiconductor polymer selected from solvent-soluble polyaniline, polythiophene, polypyrrole and their derivatives is preferably used. The shoe sole further includes a subsidiary sole. Each stiffener is positioned in a corresponding retaining space of the housing and includes opposite first and second portions, and a third portion. The apparatus forms one image by integrating images at the same point acquired by the cameras, respectively without being synchronized the cameras with each other and using any external sensor. In some embodiments the storage module capacity model is a function fitted to data points representing the values of item-size descriptors of fully-stowed storage modules.