Weather balloon Weather balloon A weather or sounding balloon is a balloon (specifically a type of high-altitude balloon) that carries instruments aloft to send back information on atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde. To obtain wind data, they can be tracked by radar, radio direction finding, or navigation systems (such as the satellite-based Global Positioning System, GPS). Balloons meant to stay at a constant altitude for long periods of time are known as transosondes. Weather balloons that do not carry an instrument pack are used to determine upper-level winds and
Single crossing condition ordered set. Such situations appear often in information economics, contract theory, social choice and political economics, among other fields. The term Single-Crossing Condition (Spence Mirrlees property) refers to the requirement that the isoutility curve for agents of different types cross only once. This condition guarantees that the transfer in a incentive-compatible direct mechanism can be pinned down by the transfer of the lowest type. This condition is similar to another condition called Strict Increasing Difference (SID). Formally, suppose the agent has a utility function formula_7, the SID says formula_8 we have formula_9. The Spence-Mirrlees Property is characterized by formula_10. Single