The NCAA will announce the 20 at-large bids, seedings and brackets late this afternoon for its 48-team Division I men's basketball championship tournament.

The other 28 teams receive automatic bids as conference champions, either on the basis of regular-season results or a tournament. The determination is left up to each conference. In the Big Ten, Pac-10, Ivy League and the Western Athletic Conference, the regular-season winner gets an automatic bid; tournament champions earn bids in the other 24.

The other 20 teams are selected by the nine-member Division I Men's Basketball Committee, chaired by Dave Gavitt, athletic director at Providence and commissioner of the Big East Conference. The committee has been meeting in Kansas City since Thursday.

Other committee members are: Ladell Andersen, Utah State athletic director; Vic Bubas, Sun Belt Conference commissioner; Ben Carnevale, a member of the athletic staff at James Madison University; Gene Corrigan, Notre Dame athletic director; Andy Geiger, Stanford athletic director; Dave Hart, Missouri athletic director; Dick Shrider, Miami (Ohio) athletic director, and Frank Windegger, Texas Christian University athletic director.

This committee selects the 20 best at-large teams, regardless of location. It also is responsible for seeding the teams from first to 48th and then balancing the four regionals. As a result, some teams--both at-large and automatic qualifiers--may be moved to regionals away from their location.

According to the basketball championship handbook, the following criteria are used to make the at-large selections: "a) eligiblity status of student-athletes for postseason competition and b) won-lost record considering strength of schedule." The committee is helped in this task by a computer that, among other things, lists won-lost percentage of opponents.

The top 16 seeds receive first-round byes, four in each regional. First- and second-round games will be played at Charlotte, N.C., (Thursday, Saturday) and Uniondale, N.Y., (Friday, Sunday) in the East Regional; Tulsa (Thursday, Saturday) and Dallas (Friday, Sunday) in the Midwest; Nashville (Thursday, Saturday) amd Indianapolis (Friday, Sunday) in the Mideast, and Logan, Utah, (Thursday, Saturday) and Pullman, Wash., (Friday, Sunday) in the West.

The East Regional is scheduled at Raleigh, N.C., March 19, 21; the Midwest at St. Louis March 19, 21; the Mideast at Birmingham, Ala., March 18, 20, and the West at Provo, Utah, March 18, 20. The East champion plays the Midwest winner March 27 in one national semifinal at New Orleans; the other semifinal pairs the Mideast and West winners. The championship game starts at 9:12 p.m. Eastern Standard Time on March 29.

For the first time, there are no third-place games at any level.