Hardware/software partitioning is a key issue in the design of embedded systems when performance constraints have to be met and chip area and/or power dissipation are critical. For that reason, diverse approaches to automatic hardware/software partitioning have been proposed since the early 1990s. In all approaches so far, the granularity during partitioning is fixed, i.e., either small system parts (e.g., base blocks) or large system parts (e.g., whole functions/processes) can be swapped at once during partitioning in order to find the best hardware/software tradeoff. Since the deployment of a fixed granularity is likely to result in suboptimum solutions, we present the first approach that features a flexible granularity during hardware/software partitioning. Our approach is comprehensive in so far that the estimation techniques, our multigranularity performance estimation technique described here in detail, that control partitioning, are adapted to the flexible partitioning granularity. In addition, our multilevel objective function is described. It allows us to tradeoff various design constraints/goals (performance/hardware area) against each other. As a result, our approach is applicable to a wider range of applications than approaches with a fixed granularity. We also show that our approach is fast and that the obtained hardware/software partitions are much more efficient (in terms of hardware effort, for example) than in cases where a fixed granularity is deployed.

Dynamic load balancing in multicomputers can improve the utilization of processors and the efficiency of parallel computations through migrating workload across processors at runtime. We present a survey and critique of dynamic load balancing strategies that are iterative: workload migration is carried out through transferring processes across nearest neighbor processors. Iterative strategies have become prominent in recent years because of the increasing popularity of point-to-point interconnection networks for multicomputers. Key words: dynamic load balancing, multicomputers, optimization, queueing theory, scheduling. INTRODUCTION Multicomputers are highly concurrent systems that are composed of many autonomous processors connected by a communication network 1;2 . To improve the utilization of the processors, parallel computations in multicomputers require that processes be distributed to processors in such a way that the computational load is evenly spread among the processors...

A clustering and ordination algorithm suitable for mining extremely large databases, including those produced by microarray expression studies, is described and analyzed for stability. Data from a yeast cell cycle experiment with 6000 genes and 18 experimental measurements per gene are used to test this algorithm under practical conditions. The process of assigning database objects to an X, Y coordinate, ordination, is shown to be stable with respect to random starting conditions, and with respect to minor perturbations in the starting similarity estimates. Careful analysis of the way clusters typically co-locate, versus the occasional large displacements under different starting conditions are shown to be useful in interpreting the data. This extra stability information is lost when only a single cluster is reported, which is currently the accepted practice. However, it is believed that the approaches presented here should become a standard part of best practices in analyzing computer clustering of large data collections.

In this paper, we introduce a parallel simulated annealing algorithm for generating aesthetically pleasing straight-line drawings. The proposed algorithm calculates high quality 3D layouts of arbitrary undirected graphs. Due to the 3D layouts, structure information is presented to the human viewer at a glance. The computing time of the algorithm is reduced by a new parallel method for exploiting promising intermediate configurations. As the algorithm avoids running into a local minimum of the cost function, it is applicable for the animation of graphs of reasonably larger size than it was possible before. Subsequent to the discussion of the algorithm, empirical data for the performance of the algorithm and the quality of the generated layouts are presented.

A novel dynamic link architecture based on multiscale morphological dilation-erosion is proposed for face verification in a cooperative scenario where the candidates claim an identity that is to be checked. The performance of the morphological dynamic link architecture (MDLA) is evaluated in terms of the receiver operating characteristic (ROC) for several threshold selections on the matching error in the M2VTS database. The experimental results indicate that the proposed method outperforms the dynamic link matching with Gabor based feature vectors. 1 Introduction Face recognition has exhibited a tremendous growth for more than two decades. A critical survey of the literature related to human and machine face recognition can be found in [1]. Two main categories for face recognition techniques are identified: those employing geometrical features and those using grey-level information (e.g. the eigenface approach). An approach that exploits both sources of information, that is, the grey...

We investigate a new approach for reproducing color images. Rather than mapping the colors in an image onto the gamut of colors that can be printed with cyan, magenta, yellow, and black inks, we choose the set of printing inks for the particular image being reproduced. In this paper, we look at the special case of selecting inks for duotone printing, a relatively inexpensive process in which just two inks are used. Specifically, the system we describe takes an image as input, and allows a user to select 0, 1, or 2 inks. It then chooses the remaining ink or inks so as to reproduce the image as accurately as possible and produces the appropriate color separations automatically. CR Categories: I.3.4 [Computer Graphics]: Graphics Utilities Additional Keywords: color reproduction, color printing, duotone, gamut mapping, Neugebauer model 1 Introduction Modern color reproduction typically employs a fixed set of processcolor inks: cyan, magenta, yellow, and sometimes black. Placed on top ...

Hardware/software partitioning is one of the key issues in hardware/software co-design. The system COSYMA uses simulated annealing based on estimated costs. Deviations between estimations and real costs seem unavoidable due to synthesis, compiler and communication effects. This paper describes an approach to adapt the estimation. The results show fast convergence of estimated to real costs.

This paper reports about research projects of the University of Paderborn in the field of distributed combinatorial optimization. We give an introduction into combinatorial optimization and a brief definition of some important applications. As a first exact solution method we describe branch & bound and present the results of our work on its distributed implementation. Results of our distributed implementation of iterative deepening conclude the first part about exact methods. In the second part we give an introduction into simulated annealing as a heuristic method and present results of its parallel implementation. This part is concluded with a brief description of genetic algorithms and some other heuristic methods together with some results of their distributed implementation.

We investigate the problem of mapping dynamically generated tasks onto the processors of an MIMD-system. Our main concern is to construct an algorithm which can be integrated in distributed runtime systems like PVM or MPI. An algorithm which is suitable for this purpose has to be scalable for massively parallel systems and has to be adaptive to different architecture- and application-characteristics. Existing methods are often not adjustable to different architecture- and applicationdemands. Even if they are, the adjustment has to be done by hand via time-consuming experiments. A universally applicable strategy has to adjust its parameters automatically according to hardware- and application-characteristics. We concentrate on bidding-algorithms which check the load of K randomly selected processors before placing a task. The analysis of this method is based on a model which allows predictions of the behaviour of the scheduler. Especially for a large number n of processes it is possible...

In this paper, we present a problem independent general purpose parallel implementation of simulated annealing on distributed message-passing multiprocessor systems. The sequential algorithm is studied and we give a classi#cation of combinatorial optimization problems together with their neighborhood structures. Several parallelization approaches are examinedconsidering their suitability for problems of the various classes. For typical representatives of the di#erent classes goodparallel simulated annealing implementations arepresented.