We study the two-level uncapacitated facility location (TUFL) problem. Given two types of facilities, which we call y-facilities and z-facilities, the problem is to decide which facilities of both types to open, and to which pair of yand z-facilities each client should be assigned, in order to satisfy the demand at maximum profit. We first present two multi-commodity How formulations of TUFL an...

GSM call re-establishment service allows a mobile station to resume a call in which the radio link has been temporarily interrupted due to interference or bad signal (which is referred to as an interrupted call). This service increases end user satisfaction and network quality perception. In this paper, we propose analytic models to study the performance for call re-establishment service. Our s...

OBJECTIVE The long-term care (LTC) sector in Canada is expanding, but little attention has been given to medical human resources in this area. Our objective was to seek LTC medical directors' opinions about medical services in LTC and about strategies for recruitment and retention. DESIGN Mailed survey. SETTING Long-term care facilities and nursing homes. PARTICIPANTS Seven hundred five m...