An improved load leveling yarn has a force-displacement profile that maintains desirable properties of previously known yarns, but exhibits a lower elongation at a stress that is greater than the IBS but less than or equal to 1. Also, in a hierarchized route, the collection device determines a network topology of a route in a specific hierarchy based on opposed topology information in the hierarchy and opposed topology information of a route in another hierarchy. A code block number estimation unit estimates the numbers of code blocks in one packet using the packet size and the code block sizes for individual operation modes. The method can also include the step of, in response to a forward trick mode command, modifying at least the number of non-prediction source pictures in the group of pictures to convert the progressive video signal to a trick mode video signal. The heat exchanger is manufactured using first and second fixtures having first and second sets of parallel ribs which are received in respective second and first troughs of the corrugated sheet.