Abstract: The present invention provides an apparatus for measuring the concentration of a constituent to be detected in exhaust gas, which apparatus is capable of detecting with a high accuracy the concentration of the constituent to be detected in exhaust gas even though oxygen concentration in the exhaust gas varies. In an exhaust gas sensor 1 for use in the measuring apparatus, exhaust gas is introduced into spaces 15, 16 on both sides of an oxygen concentration cell element 4, and the oxidation catalyst activities of first to third electrodes 11 to 13 are adjusted so that there occurs a difference between the space 15 and the space 16 in consumption of the constituent to be detected, which consumption is caused by the oxidation of the constituent. Thus a concentration cell electromotive force is generated in the oxygen concentration cell element 4, and an oxygen pump element 3 pumps oxygen into or out of the space 15 so that the electromotive force is held at an target value EC not more than 10 mV.

Abstract: A document detection system using a detection result presentation that can facilitate a user's quick comprehension of the relevancy of each detected document. In this system, a user's input for commanding a document detection is analyzed to extract keywords and viewpoints relevant to each keyword contained in the user's input, and a detection command is constructed from the keywords and the viewpoints extracted from the user's input. Then, the detection operation is executed to detect those documents among a plurality of stored documents which match with the constructed detection command as detected documents for a detection result. The detection result can be presented in the multi-dimensional display formed by setting the viewpoints to axes with the detection command as an origin and using distances of the detected documents with respect to the origin for each viewpoint as coordinates of the detected documents with respect to each axis representing each viewpoint.