Recent advancement in personal communication services (PCS) provides wireless multimedia services for users on the move. For establishing the convenient access environment, the evolution of IP-based integrated scheme becomes very urgent for public wireless access systems. In this paper, we clarify the well-known issues of integrating the general packet radio service (GPRS) network and IEEE 802.11 wireless local area network (WLAN). These issues include the inconsistence in transmission rate and coverage area, the difficulty in seamless handoff, the complexities of mobile IP and address translations, and so on. Based on classified cases, we propose the circular probe strategy (CPS) to solve the IP translations and measure the precise handoff latency of a mobile node roaming from one network to another. This latency information helps a mobile node and its home agent (HA) to decide the appropriate handoff timing, to maximize the data transmission rate, and to perform seamless handoff in the heterogeneous system. We also proposed the smart access point (AP) mechanism to reduce the overhead of CPS and to provide precise handoff latency information for mobile nodes (MNs) to select the most appropriate AP for association. Experiment results demonstrate that the proposed smart handoff scheme performs better than traditional algorithms in terms of handoff time in the integrated network.

Process-centered software engineering environments (PSEEs) facilitate controlling software processes. Many issues related to PSEEs such as process evolution support have been addressed. We identify an unsolved issue, which is preventing information leakage when the process is being enacted. We developed a model called PsACL for the prevention. This paper proposes PsACL, which offers the following features: (a) controlling both read and write access of software products, (b) preventing indirect information leakage, (c) managing role associations, (d) managing role hierarchies, (e) enforcing static and simple dynamic separation-of-duty constraints, (f) allowing declassification of products, and (g) allowing access control information exchange among software processes.