62538887
Nicarus: A distributed verilog compiler
Software design tools, such as compilers and simulators, are widely used in the integrated circuits (IC) industry. As the circuit complexity grows, better and faster tools are required. One way to speed up a software system is to parallelize it and execute it on multiple CPUs. This idea is particularly appealing when it comes to the compilers for hardware description languages (HDL). In this paper, we explore the parallelization of a Verilog compiler on a network of computers using Parallel Virtual Machine (PVM). Our design parallelizes the three most important and time-consuming phases of the compilation process while minimizing the communications overhead. Experimental results reveal that the algorithms used for parallelizing the compiler results in a speedup of the compilation process.
1836730
Compiled Code in Distributed Logic Simulation
A logic simulation approach known as compiled-code event-driven simulation was developed in the past for sequential logic simulation. It improves simulation performance by reducing the logic evaluation and propagation time. In this paper we describe the application of this approach to distributed logic simulation. Our experimental results show that using compiled code can greatly improve the stability and overall performance of a time-warp based logic simulator. We also present a technique called fanout aggregation that makes use of information on circuit partitions and considerably improves the run-time performance of our (distributed) compiled code simulator. It does not produce a similar improvement when used in conjunction with an interpreted simulator because of run-time overhead
206565969
Immunity of Complete Problems
Abstract Two necessary and sufficient conditions for all E -complete sets to contain dense P subsets are shown. We then prove that every ≤ p m -hard for E set and its complement contain dense E ∩UP subsets. As a corollary, every NE -complete set and its complement contain dense E ∩UP subsets.
8350188
Constraint Propagation And Progressive Verification For Component-Based Process Model
System assembly is one of the major issues in engineering complex component-based systems. This is especially true when heterogeneous, COTS and GOTS distributed systems, typical in industrial applications, are involved. The goal of system assembly is not only to make constituent components work together, but also to ensure that the components as a whole behave consistently and guarantee certain end-to-end properties. Despite recent advances, there is a lack of understanding about software composability, as well as theory and techniques for checking and verifying component-based systems. A theory of software system constraints about components, their environment and about system as a whole is the necessary foundation toward solid understanding of the composability of component-based systems. In this paper, we present a systematic approach for constraint specification and constraint propagation in concert with design refinement with a novel technique to ensure consistency between system-wide and component constraints in a design composition process of component-based systems. The consistent constraint propagation is used in our approach to drive progressive verification of the design. It allows us to verify overall design composition without interference of internal details of component designs. Verification is done separately at architectural and component levels without having to compose results of component analyses. A component can be safely replaced with alternative design without re-verifying the overall system composition so long as the replacement conforms to the corresponding interface and component constraint(s).
16977232
Incremental exploration of the combined physical and behavioral design space
Achieving design closure is one of the biggest headaches for modern VLSI designers. This problem is exacerbated by high-level design automation tools that ignore increasingly important factors such as the impact of interconnect on the area and power consumption of integrated circuits. Bringing physical information up into the logic level or even behavioral-level stages of system design is essential to solve this problem. In this paper, we present an incremental floorplanning high-level synthesis system. This system integrates high-level and physical design algorithms to concurrently improve a system's schedule, resource binding, and floor-plan, thereby allowing the incremental exploration of the combined behavioral-level and physical-level design space. Compared with previous approaches that repeatedly call loosely coupled floorplanners for physical estimation, this approach has the benefit of efficiency, stability, and better quality of results. For designs containing functional units with non-unity aspect ratios, the average CPU time improved by 369 %, the area improved by 14.24 %, and power improved by 4 %.
9700223
Discovering Frequent Closed Partial Orders from Strings
Mining knowledge about ordering from sequence data is an important problem with many applications, such as bioinformatics, Web mining, network management, and intrusion detection. For example, if many customers follow a partial order in their purchases of a series of products, the partial order can be used to predict other related customers' future purchases and develop marketing campaigns. Moreover, some biological sequences (e.g., microarray data) can be clustered based on the partial orders shared by the sequences. Given a set of items, a total order of a subset of items can be represented as a string. A string database is a multiset of strings. In this paper, we identify a novel problem of mining frequent closed partial orders from strings. Frequent closed partial orders capture the nonredundant and interesting ordering information from string databases. Importantly, mining frequent closed partial orders can discover meaningful knowledge that cannot be disclosed by previous data mining techniques. However, the problem of mining frequent closed partial orders is challenging. To tackle the problem, we develop Frecpo (for frequent closed partial order), a practically efficient algorithm for mining the complete set of frequent closed partial orders from large string databases. Several interesting pruning techniques are devised to speed up the search. We report an extensive performance study on both real data sets and synthetic data sets to illustrate the effectiveness and the efficiency of our approach
411372
Stratification Approach to Modeling Video
The explosive growth of audiovisual information in the last few years has made the development of advanced video modeling and management tools an urgent task. In this research, we investigate the use of stratification approach to model the contextual information of video contents as multi-layered strata. By judiciously choosing the right level and types of strata, we are able to automate a major part of the strata extraction process. Using the strata as the basis, we have developed advanced functionalities to support the flexible retrieval and content-based browsing of video. A prototype has been developed to support the whole process of video management, from strata extraction, to indexing, retrieval and browsing. The prototype is tested in the domain of news video and the system has been found to be effective.