DALLAS, May 23 -- Allied Riser Communications Corp., an installer of fiber optic networks in office buildings, said it has cut its workforce by 117 employees, or about 23 percent, to trim costs. The company said the cuts include an unspecified number of losses from attrition since February 15, 2001. Shares of Allied Riser closed at $1.03, down 5 cents on the Nasdaq exchange. The shares have ranged as high as $18.38 and as low as 60 cents in the past year.