38988284
Perfectly Overlapped Generation of Long Runs for Sorting Large Files
A parallel algorithm is presented for quick generation of long sorted runs as the first phase of sorting a large file. It can generate runs of length about 2(m + 2)p on a linear array of p processors each with a heap of size m. Internal computations can be completely overlapped with I/O, and only n + (m + 2)p steps are required to generate the runs from a file of n items. Experiments with the algorithm show that it can give highly satisfactory results in a real environment. A variant of the algorithm is also presented. It is possible that no merge phase is required for sorting a file occupying a whole disk.
28386887
New Systolic Arrays for the Longest Common Subsequence Problem
Abstract New systolic arrays are presented to solve the longest common subsequence (LCS) problem. The first array is based on a previous work to compute the length of an LCS. The second array improves on the first one. The second array is about 1 4 faster than the first array, and each processing element (PE) of the second array requires one less port for both input and output to transfer one less value. Either of the two arrays can be equipped with a content-addressable memory in each PE to recover an LCS. The resulting array requires fewer steps than the previously proposed one.
5110930
A comparison study of the two-tier and the single-tier personal communications services systems
A two-tier PCS system integrates the high tier PCS system and the low tier PCS systems into a single system to provide the advantages of both tiers. Such a system is expected to provide better service (more available and more cost effective to the users) at the expense of the extra tier switching management. We compare the performance of the two-tier PCS system and the single low tier system in two aspects: the registration traffic and the service availability. Because of the tier management, the two-tier system generates more registration traffic than the single low tier system. Under the range of the input parameters in our study, we show that the two-tier system generates less than 10% extra registration traffic than the single low tier system in most cases and generates less than 20% registration traffic in the worst cases. It is clear that for the service availability, the two-tier system is better than the single one tier system. We also study the probability that a call is forced terminated in the single low tier system because the low tier becomes unavailable during the call (such a call can be continued in the two-tier system).
195838526
LiB: a cell layout generator
An automatic layout generation system, called LiB, for the library cells used in CMOS ASIC design is presented. LiB takes a transistor-level circuit schematic in SPICE format and outputs a symbolic layout. In LiB, the intra-cell routing runs not only between PMOS and NMOS but also on diffusion islands as well as the two side regions (one between the PMOS diffusion and the power line, and the other between the NMOS diffusion and the ground line). Several heuristic algorithms are proposed to solve the transistor-clustering, -pairing, -chaining, -folding, the chain placement, the routing, and the net assignment problems. Experimental results are presented to show the capability of LiB.<<ETX>>
10935949
A time-division algorithm for parallel simulation
Most parallel simulation algorithms (e.g., Chandy and Misra’s algorithm or the Time Warp algorithm) are based on a “space-division” approach. The parallelism of this approach is limited by the causality constraints. Another approach, the “time-division” approach, may provide more parallelism if the time domain is appropriately partitioned. We present a time-division parallel simulation algorithm that partitions the time domain via state matching, We show that linear speed up can be achieved. For a complex system, the best parallel simulation approach is to integrate “time-division” and “space-division” algorithms: the simulated system is partitioned into several subsystems; a subsystem may be simulated by the time-division approach (e. g., our algorithm), while the overall system is simulated by the space-division approach.
206549585
vGPRS: a mechanism for voice over GPRS
This paper proposes vGPRS, a voice over IP (VoIP) mechanism for a general packet radio service (GPRS) network. In this approach, a new network element called VoIP mobile switching center (VMSC) is introduced to replace standard GSM MSC. The vGPRS approach is implemented using standard H.323, GPRS, and GSM protocols. Thus, existing GPRS and H.323 network elements are not modified. Furthermore, both standard GSM and GPRS mobile stations can be used to receive vGPRS service, which need not be equipped with the VoIP (i.e., H.323) terminal capabilities.
6741785
Modeling PCS networks under general call holding time and cell residence time distributions
In a personal communication service (PCS) network, the call completion probability and the effective call holding times for both complete and incomplete calls are central parameters in the network cost/performance evaluation. These quantities will depend on the distributions of call holding times and cell residence times. The classical assumptions made in the past that call holding times and cell residence times are exponentially distributed are not appropriate for the emerging PCS networks. This paper presents some systematic results on the probability of call completion and the effective call holding time distributions for complete and incomplete calls with general cell residence times and call holding times distributed with various distributions such as gamma, erlang, hyperexponential, hyper-erlang, and other staged distributions. These results provide a set of alternatives for PCS network modeling, which can be chosen to accommodate the measured data from PCS field trials. The application of these results in billing rate planning is also discussed.