In this paper, we describe a distributed transactional workflow system named ICU/COWS, which supports multiple workflow types of large scale enterprises. The system aims to support the whole workflow for large scale enterprises effectively within a single workflow system and the system is designed to satisfy several design goals such as availability, scalability, and reliability. Transactional task and special tasks such as alternative task and compensating task are developed and utilized to achieve the design goals in task model level and the system is constructed with distributed transactional objects to achieve the design goals in distributed system environment. In this paper, structured ad hoc workflow is defined as a special type of ad hoc workflow that should be automated by workflow management system because many benefits can be obtained by automating it and connector facility is proposed as a means to support structured ad hoc workflow effectively. Some characteristics of a workflow system can be identified by monitoring the system behavior on different conditions like workloads or system configurations. An early version of the system has been implemented and the performance data of the system is illustrated.

Existing research related to RSVP with mobility support has mainly focused on maintaining reservation state along the routing path, which changes continuously with the movements of mobile host (MH), without much overhead and delay. However, problems such as deepening RSVP's inherent scalability problem and requiring significant changes in the existing network infrastructure have not been adequately addressed. In this paper, we propose a new approach, known as Concatenation and Optimization for Reservation Path (CORP), which addresses these issues. In CORP, each BS pre-establishes pseudo reservations to its neighboring BSs in anticipation of the MH's movement. When the MH moves into another wireless cell, the associated pseudo reservation is activated and concatenated to the existing RSVP session to guarantee continuous QoS support. Because a pseudo reservation is recognized as a normal RSVP session by intermediate routers, little change is required in the current Internet environment to support both movements within a single routing domain and between two different routing domains. CORP also dynamically optimizes the extended reservation path to avoid the infinite path extension problem. Multicast addressing is used to further reduce resource consumption in the optimization process. The experimental results of the CORP implementation demonstrate that it significantly reduces the delay and overhead caused by handoffs compared to the case of establishing a new RSVP session. The improvement increases as the distance between the MH and its correspondent host (CH) grows.