Based on software radio, a novel digital-IF receiver is introduced from the engineering point of view. Through the cooperation between programmable logic device (PLD) and high performance digital signal processor (DSP), all functions of receiver can be reconfigured online. As long as the bandwidth of the input IF signal is within an allowed range, the different signals can be received by reconfiguring the receiver online via PCI or Ethernet, without any hardware modification.

We consider the view data lineage problem in a warehousing environment: for a given data item in a materialized warehouse view, we want to identify the set of source data items that produced the view item. We formalize the problem and we present a lineage tracing algorithm for relational views with aggregation. Based on our tracing algorithm, we propose a number of schemes for storing auxiliary views that enable consistent and efficient lineage tracing in a multi-source data warehouse. We report on a performance study of the various schemes, identifying which schemes perform best in which settings. Based on our results, we have implemented a lineage tracing package in the WHIPS data warehousing system prototype at Stanford. With this package, users can select view tuples of interest, then efficiently "drill through" to examine the exact source tuples that produced the view tuples of interest.

Some commercial data warehousing systems support schema-level lineage tracing, or provide specialized drill-down and/or drill-through facilities for multi-dimensional warehouse views. Our lineage tracing system supports more fine-grained instance-level lineage tracing for arbitrarily complex relational views, including aggregation. At view definition time, our system automatically generates lineage tracing procedures and supporting auxiliary views. At lineage tracing time, the system applies the tracing procedures to the source tables and/or auxiliary views to obtain the lineage results and to illustrate the specific view data derivation process.

We consider the view data lineage problem in a warehousing environment: For a given data item in a materialized warehouse view, we want to identify the set of source data items that produced the view item. We formally define the lineage problem, develop lineage tracing algorithms for relational views with aggregation, and propose mechanisms for performing consistent lineage tracing in a multisource data warehousing environment. Our result can form the basis of a tool that allows analysts to browse warehouse data, select view tuples of interest, and then “drill-through” to examine the exact source tuples that produced the view tuples of interest.

Increasing demand for wireless mobile communications, coupled with limited network resources, has motivated investigation into alternative efficient mobility management solutions. We consider wireless PCS call setup protocols. We propose a lightweight location lookup protocol, which significantly reduces the network signaling and setup delay during call setup. As an alternative, we consider a reverse connection setup protocol that also performs efficient call setup, while minimizing the cost of failed call attempts. The two protocols have different advantages, in particular when combined with location management techniques including HLR/VLR, HLR/VLR with partial replication, and HLR/VLR with caching. We study the combinations of call setup protocols with location management techniques and compare their performance to find the most efficient call setup schemes. Both analytical and simulation results are presented.