9707498
Efficient test solutions for core-based designs
A test solution for a complex system requires the design of a test access mechanism (TAM), which is used for the test data transportation, and a test schedule of the test data transportation on the designed TAM. An extensive TAM will lead to lower test-application time at the expense of higher routing costs, compared to a simple TAM with low routing cost but long testing time. It is also possible to reduce the testing time of a testable unit by loading the test vectors in parallel, thus increasing the parallelization of a test. However, such a test-time reduction often leads to higher power consumption, which must be kept under control since exceeding the power budget could damage the system under test. Furthermore, the execution of a test requires resources and concurrent execution of tests may not be possible due to resource or other conflicts. In this paper, we propose an integrated technique for test scheduling, test parallelization, and TAM design, where the test application time and the TAM routing are minimized, while considering test conflicts and power constraints. The main features of our technique are the efficiency in terms of computation time and the flexibility to model the system's test behavior, as well as the support for the testing of interconnections, unwrapped cores and user-defined logic. We have implemented our approach and made several experiments on benchmarks as well as industrial designs in order to demonstrate that our approach produces high-quality solution at low computational cost.
27568459
Automated transformation of algorithms into register-transfer level implementations
This paper describes a high-level synthesis system, called CAMAD, for transforming algorithms into hardware implementation structures at register-transfer level. The algorithms are used to specify the behaviors of the hardware to be designed. They are first translated into a formal representation model which is based on timed Petri nets and consists of separate but related descriptions of control and data path. The formal model is used as an intermediate design representation and supports an iterative transformation approach to high-level synthesis. The basic idea is that once the behavioral specification is translated into the initial design representation, it can be viewed as a primitive implementation. Correctness-preserving transformations are then used to successively transform the initial design into an efficient implementation. Selection of transformations is guided by an optimization strategy which makes design decisions concerning operation scheduling, data path allocation, and control allocation simultaneously. The integration of these several synthesis subtasks has resulted in a better chance to reach the globally optimal solution. Experimental results show that our approach produces improved register-transfer designs, especially in the cases when the designed hardware consists of data paths and control logics that are tightly coupled. >
62487698
The Design and Optimization of SOC Test Solutions
We propose an integrated technique for extensive optimization of the final test solution for System-on-Chip using Simulated Annealing. The produced results from the technique are a minimized test schedule fulfilling test conflicts under test power constraints and an optimized design of the test access mechanism. We have implemented the proposed algorithm and performed experiments with several benchmarks and industrial designs to show the usefulness and efficiency of our technique.
9900155
An approach to incremental design of distributed embedded systems
In this paper we present an approach to incremental design of distributed embedded systems for hard real-time applications. We start from an already existing system running a set of applications and the design problem is to implement new functionality so that the already running applications are not disturbed and there is a good chance that, later, new functionality can easily be added to the resulted system. The mapping and scheduling problem are considered in the context of a realistic communication model based on a TDMA protocol.
43554221
Online and Dynamic Recognition of Squarefree Strings
The online squarefree recognition problem is to detect the first occurrence of a square in a string whose characters are provided as input one at a time. We present an efficient algorithm to solve this problem for strings over arbitrarily ordered alphabets. Its running time is O(n log n), where n is the ending position of the first square, which matches the running times of the fastest known algorithms for the analogous offline problem. We also present a very simple algorithm for a dynamic version of the problem over general alphabets in which we are initially given a squarefree string, followed by a series of updates, and the objective is to determine after each update if the resulting string contains a square and if so, report it and stop.
36553676
Time and Space Efficient Algorithms for Constrained Sequence Alignment
In this paper, we study the constrained sequence alignment problem, which is a generalization of the classical sequence alignment problem with the additional constraint that some characters in the alignment must be positioned at the same columns. The problem finds important applications in Bioinformatics. Our major result is an O(ln2)-time and O(ln)-space algorithm for constructing an optimal constrained alignment of two sequences where n is the length of the longer sequence and l is the length of the constraint. Our algorithm matches the best known time complexity and reduces the best known space complexity by a factor of n for solving the problem. We also apply our technique to design time and space efficient heuristic and approximation algorithm for aligning multiple sequences.
43458709
Algorithms for Local Forest Similarity
An ordered labeled tree is a rooted tree, where the left-to-right order among siblings is significant and each node associates a label. A forest is a sequence of ordered labeled trees. Suppose F is a forest. A substructure is a connected subgraph of F. Define a subforest as a sequence of substructures of F such that their roots are siblings. The local forest similarity problem for forests F and G is to find two most similar subforests of F and G. We answer an open problem in Paper [3], and provide efficient algorithms on it. Comparing with previous results, our algorithms achieve better performance.
40452783
A Buffering/Caching Mechanism for Continous Media Players
In order to reduce the playback discontinuity of a stream of data (audio for example) sent through a packet-switched network, we proposed a buffering/caching mechanism for continuous media players. The stream playback is usually implemented by two parallel processes: receiving and playing. The former receives stream chips from the network while the latter plays the received stream chips and then empties their occupied buffers for the former. Our buffering/caching mechanism makes the receiving process completely independent of the playing process. Thus, the receiving process does not need to wait for the playing process to empty buffers so that the network bandwidth can be used as much as possible. Because the cached stream chips can be played from the local disk, the response latency of the playback control operations such as REPLAY and REWIND can be reduced as well. The mechanism was developed for our hyper audio web system.
8351252
Using object deputy model to prepare data for data warehousing
Providing integrated access to multiple, distributed, heterogeneous databases and other information sources has become one of the leading issues in database research and the industry. One of the most effective approaches is to extract and integrate information of interest from each source in advance and store them in a centralized repository (known as a data warehouse). When a query is posed, it is evaluated directly at the warehouse without accessing the original information sources. One of the techniques that this approach uses to improve the efficiency of query processing is materialized view(s). Essentially, materialized views are used for data warehouses, and various methods for relational databases have been developed. In this paper, we first discuss an object deputy approach to realize materialized object views for data warehouses which can also incorporate object-oriented databases. A framework has been developed using Smalltalk to prepare data for data warehousing, in which an object deputy model and database connecting tools have been implemented. The object deputy model can provide an easy-to-use way to resolve inconsistency and conflicts while preparing data for data warehousing, as evidenced by our empirical study.