Results 1  10
of
74
No Free Lunch Theorems for Optimization
, 1997
"... A framework is developed to explore the connection between effective optimization algorithms and the problems they are solving. A number of “no free lunch ” (NFL) theorems are presented which establish that for any algorithm, any elevated performance over one class of problems is offset by performan ..."
Abstract

Cited by 928 (10 self)
 Add to MetaCart
A framework is developed to explore the connection between effective optimization algorithms and the problems they are solving. A number of “no free lunch ” (NFL) theorems are presented which establish that for any algorithm, any elevated performance over one class of problems is offset by performance over another class. These theorems result in a geometric interpretation of what it means for an algorithm to be well suited to an optimization problem. Applications of the NFL theorems to informationtheoretic aspects of optimization and benchmark measures of performance are also presented. Other issues addressed include timevarying optimization problems and a priori “headtohead” minimax distinctions between optimization algorithms, distinctions that result despite the NFL theorems’ enforcing of a type of uniformity over all algorithms.
A Graduated Assignment Algorithm for Graph Matching
, 1996
"... A graduated assignment algorithm for graph matching is presented which is fast and accurate even in the presence of high noise. By combining graduated nonconvexity, twoway (assignment) constraints, and sparsity, large improvements in accuracy and speed are achieved. Its low order computational comp ..."
Abstract

Cited by 382 (16 self)
 Add to MetaCart
A graduated assignment algorithm for graph matching is presented which is fast and accurate even in the presence of high noise. By combining graduated nonconvexity, twoway (assignment) constraints, and sparsity, large improvements in accuracy and speed are achieved. Its low order computational complexity [O(lm), where l and m are the number of links in the two graphs] and robustness in the presence of noise offer advantages over traditional combinatorial approaches. The algorithm, not restricted to any special class of graph, is applied to subgraph isomorphism, weighted graph matching, and attributed relational graph matching. To illustrate the performance of the algorithm, attributed relational graphs derived from objects are matched. Then, results from twentyfive thousand experiments conducted on 100 node random graphs of varying types (graphs with only zeroone links, weighted graphs, and graphs with node attributes and multiple link types) are reported. No comparable results have...
Experiences with the amoeba distributed operating system
 Communications of the ACM
, 1990
"... The Amoeba distributed operating system has been in development and use for over eight years now. In this paper we describe the present system and our experience with it—what we did right, but also what we did wrong. Among the things done right were basing the system on objects, using a single unifo ..."
Abstract

Cited by 229 (20 self)
 Add to MetaCart
(Show Context)
The Amoeba distributed operating system has been in development and use for over eight years now. In this paper we describe the present system and our experience with it—what we did right, but also what we did wrong. Among the things done right were basing the system on objects, using a single uniform mechanism (capabilities) for naming and protecting them in a location independent way, and designing a completely new, and very fast file system. Among the things done wrong were having threads not be preemptable, initially building our own homebrew window system, and not having a multicast facility at the outset.
An Efficient Reliable Broadcast Protocol
 OPERATING SYSTEMS REVIEW
, 1989
"... Many distributed and parallel applications can make good use of broadcast communication. In this paper we present a (software) protocol that simulates reliable broadcast, even on an unreliable network. Using this protocol, application programs need not worry about lost messages. Recovery of comm ..."
Abstract

Cited by 152 (13 self)
 Add to MetaCart
Many distributed and parallel applications can make good use of broadcast communication. In this paper we present a (software) protocol that simulates reliable broadcast, even on an unreliable network. Using this protocol, application programs need not worry about lost messages. Recovery of communication failures is handled automatically and transparently by the protocol. In normal operation, our protocol is more efficient than previously published reliable broadcast protocols. An initial implementation of the protocol on 10 MC68020 CPUs connected by a 10 Mbit/sec Ethernet performs a reliable broadcast in 1.5 msec.
Symmetrybased Indexing of Image Databases
 J. VISUAL COMMUNICATION AND IMAGE REPRESENTATION
, 1998
"... The use of shape as a cue for indexing into pictorial databases has been traditionally based on global invariant statistics and deformable templates, on the one hand, and local edge correlation on the other. This paper proposes an intermediate approach based on a characterization of the symmetry in ..."
Abstract

Cited by 94 (7 self)
 Add to MetaCart
(Show Context)
The use of shape as a cue for indexing into pictorial databases has been traditionally based on global invariant statistics and deformable templates, on the one hand, and local edge correlation on the other. This paper proposes an intermediate approach based on a characterization of the symmetry in edge maps. The use of symmetry matching as a joint correlation measure between pairs of edge elements further constrains the comparison of edge maps. In addition, a natural organization of groups of symmetry into a hierarchy leads to a graphbased representation of relational structure of components of shape that allows for deformations by changing attributes of this relational graph. A graduate assignment graph matching algorithm is used to match symmetry structure in images to stored prototypes or sketches. The results of matching sketches and greyscale images against a small database consisting of a variety of fish, planes, tools, etc., are depicted.
OPUS: An efficient admissible algorithm for unordered search
 Journal of Artificial Intelligence Research
, 1995
"... OPUS is a branch and bound search algorithm that enables efficient admissible search through spaces for which the order of search operator application is not significant. The algorithm’s search efficiency is demonstrated with respect to very large machine learning search spaces. The use of admissibl ..."
Abstract

Cited by 91 (14 self)
 Add to MetaCart
(Show Context)
OPUS is a branch and bound search algorithm that enables efficient admissible search through spaces for which the order of search operator application is not significant. The algorithm’s search efficiency is demonstrated with respect to very large machine learning search spaces. The use of admissible search is of potential value to the machine learning community as it means that the exact learning biases to be employed for complex learning tasks can be precisely specified and manipulated. OPUS also has potential for application in other areas of artificial intelligence, notably, truth maintenance. 1.
A unified framework for tree search decoding: Rediscovering the sequential de coder
 IEEE Trans. Inform. Theory
, 2006
"... ..."
(Show Context)
Load Balancing for Distributed Branch & Bound Algorithms
, 1992
"... In this paper, we present a new load balancing algorithm and its application to distributed branch & bound algorithms. We demonstrate the efficiency of this scheme by solving some NPcomplete problems on a network of up to 256 Transputers. The parallelization of our branch & bound algorithm ..."
Abstract

Cited by 35 (7 self)
 Add to MetaCart
In this paper, we present a new load balancing algorithm and its application to distributed branch & bound algorithms. We demonstrate the efficiency of this scheme by solving some NPcomplete problems on a network of up to 256 Transputers. The parallelization of our branch & bound algorithm is fully distributed. Every processor performs the same algorithm but on a different part of the solution tree. In this case, it is necessary to distribute subproblems among the processors to achieve a well balanced workload. We present a load balancing method which overcomes the problem of search overhead and idle times by an appropriate load model and avoids trashing effects by a feedback control strategy. To show the performance of our strategy, we solved the Vertex Cover and the weighted Vertex Cover problem for graphs of up to 150 nodes, using highly efficient branch and bound algorithms. Although the computing times were very short on a 256 processor network, we were able to achieve a speedup ...
Iterative Dynamic Load Balancing in Multicomputers
 Journal of Operational Research Society
, 1994
"... 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 car ..."
Abstract

Cited by 23 (3 self)
 Add to MetaCart
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 pointtopoint 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...