  Selecting optimal resources for submitting jobs on a computational Grid or
accessing data from a data grid is one of the most important tasks of any Grid
middleware. Most modern Grid software today satisfies this responsibility and
gives a best-effort performance to solve this problem. Almost all decisions
regarding scheduling and data access are made by the software automatically,
giving users little or no control over the entire process. To solve this
problem, a more interactive set of services and middleware is desired that
provides users more information about Grid weather, and gives them more control
over the decision making process. This paper presents a set of services that
have been developed to provide more interactive resource management
capabilities within the Grid Analysis Environment (GAE) being developed
collaboratively by Caltech, NUST and several other institutes. These include a
steering service, a job monitoring service and an estimator service that have
been designed and written using a common Grid-enabled Web Services framework
named Clarens. The paper also presents a performance analysis of the developed
services to show that they have indeed resulted in a more interactive and
powerful system for user-centric Grid-enabled physics analysis.
