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Searching in Constant Time and Minimum Space
, 1995
"... This report deals with techniques for minimal space representation of a subset of elements from a bounded universe so that various types of searches can be performed in constant time. In particular, we introduce a data structure to represent a subset of N elements of [0�:::�M;1] in a number of bits ..."
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Cited by 9 (7 self)
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This report deals with techniques for minimal space representation of a subset of elements from a bounded universe so that various types of searches can be performed in constant time. In particular, we introduce a data structure to represent a subset of N elements of [0�:::�M;1] in a number of bits close to the informationtheoretic minimum and use the structure to answer membership queries in constant time. Next, we describe a representation of an arbitrary subset of points on an M M grid such that closest neighbour queries (under L1 and L1) can be performed in constant time. This structure requires M 2 + o(M 2) bits. Finally, under a byte overlap model of memory we present an M + o(M) bit, constant time solution to the dynamic onedimensional closest neighbour problem (hence, also unionsplitfind and priority queue problems) on [0�:::�M; 1].
An Exception Handling Framework for NVersion Programming in Object Oriented Systems
 in ISORC ‘00, ObjectOriented RealTime Distributed Computing, 2000 Proceedings. Third IEEE International Symposium, March 2000 Pages:226 – 233
, 2000
"... This paper proposes an approach for introducing exception handling into object oriented Nversion programming (NVP). We start with outlining general principles of structuring systems with diversity and show why it is important to use exceptions while developing and using diverselydeveloped softwar ..."
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Cited by 7 (3 self)
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This paper proposes an approach for introducing exception handling into object oriented Nversion programming (NVP). We start with outlining general principles of structuring systems with diversity and show why it is important to use exceptions while developing and using diverselydeveloped software. Internal version exceptions and external exceptions, which the diverselydesigned class can propagate, are clearly separated in our framework: each version has its own internal exceptions but the external exceptions of all versions have to be the same and identical to the interface exceptions of the whole class. This scheme requires an adjudicator of a special kind to allow interface exception signalling when a majority of versions have signalled the same exception. We demonstrate these ideas using a general framework for introducing NVP into objectoriented systems which we have developed recently [1]. This framework follows all principles of structured NVP: software diversity is introduced here at the level of classes and encapsulated into the diverselydesigned class. We discuss the internal structure of this class and the interfaces of its subcomponents; and show how the NVP controller works, version execution is coordinated and reuse operates here. This framework makes use of many advantages objectoriented programming has. For the demonstration, it has been implemented in Ada. The paper finishes with a comparison of our proposal with some existing NVP schemes and with a discussion of our future work. 1. Introduction
Parallel Maximum Sum Algorithms on Interconnection Networks
 Queen’s Uni. Dept. of Com. and
, 1999
"... We develop parallel algorithms for both onedimensional and twodimensional versions of the maximum sum problem (or max sum for short) on several interconnection networks. These algorithms are all based on a simple scheme that uses prefix sums. To this end, we first show how to compute prefix sums o ..."
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Cited by 6 (0 self)
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We develop parallel algorithms for both onedimensional and twodimensional versions of the maximum sum problem (or max sum for short) on several interconnection networks. These algorithms are all based on a simple scheme that uses prefix sums. To this end, we first show how to compute prefix sums of N elements on a hypercube, a star, and a pancake interconnection network of size p (where p N) in optimal time of O( N p + log p). For the problem of maximum subsequence sum, the 1D version of the max sum problem, we find an algorithm that computes the maximum sum of N elements on the aforementioned networks of size p, all with a running time of O( N p + log p), which is optimal in view of the trivial\Omega\Gamma N p + log p) lower bound. When p = O( N log N ), our algorithm computes the max sum in O(log N) time, resulting in an optimal cost of O(N ). This result also matches the performance of two previous algorithms that are designed to run on PRAM. Our 1D max sum algorithm can...
Speeding up Relief algorithms with kd trees
, 1998
"... There are certain problems in machine learning which desire special attention when we scale up the size of the data or move towards data mining. One of them is the problem of searching nearest neighbours of a given point in k dimensional space. If the space is ! k than kd trees can solve the prob ..."
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Cited by 5 (0 self)
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There are certain problems in machine learning which desire special attention when we scale up the size of the data or move towards data mining. One of them is the problem of searching nearest neighbours of a given point in k dimensional space. If the space is ! k than kd trees can solve the problem in asymptotically optimal time under certain conditions. We investigate the use of kd trees in nearest neighbour search in the family of attribute estimation algorithms Relief on typical machine learning databases and examine their performance under various conditions.
The Cleave And Fill Tool: An AllHexahedral Refinement Algorithm For Swept Meshes
, 2000
"... Sweeping algorithms provide the ability to generate all hexahedral meshes on a wide variety of threedimensional bodies. The work presented here provides a method to refine these meshes by first defining a path through either the source or the target mesh and next by locating the sweeping layer to ..."
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Cited by 3 (2 self)
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Sweeping algorithms provide the ability to generate all hexahedral meshes on a wide variety of threedimensional bodies. The work presented here provides a method to refine these meshes by first defining a path through either the source or the target mesh and next by locating the sweeping layer to initiate the refinement. A major contribution of this work is the ability to automatically find a minimal distance path through the target or source mesh. The refinement is accomplished by using the pillowing procedure as proposed by Mitchell. [1] Keywords: mesh generation, hexahedral meshing, refinement, sweeping, 2 D 3 samitch@sandia.gov 4 drwhite@sandia.gov 5 rjmeyer@sandia.gov Scott Mitchell, David White, and Ray Meyers work at Sandia National Laboratories, a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DEAC0494AL8500. 1. INTRODUCTION Threedimensional finite element analysis ...
Computing Graph Invariants on Rotagraphs Using Dynamic Algorithm Approach: The Case of (2,1)Colorings and Independence Numbers
, 2001
"... Rotagraphs generalize all standard products of graphs in which one factor is a cycle. A computer based approach for searching graph invariants on rotagraphs is proposed and two of its applications are presented. First, the numbers of the Cartesian product of a cycle and a path are computed, where t ..."
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Rotagraphs generalize all standard products of graphs in which one factor is a cycle. A computer based approach for searching graph invariants on rotagraphs is proposed and two of its applications are presented. First, the numbers of the Cartesian product of a cycle and a path are computed, where the number of a graph G is the minimum number of colors needed in a (2,1)coloring of G. The independence numbers of the family of the strong product graphs C 7 2 \Theta C 7 2 \Theta C 2k+1 are also obtained. Key words: rotagraph, dynamic algorithm, (2,1)coloring, independence number, Cartesian product of graphs, strong product of graphs AMS subject classification: 05C85, 05C15, 05C69, 68R10 Proposed running head: (2,1)colorings and independence numbers of rotagraphs Supported by the Ministry of Education, Science and Sport of Slovenia under the grant 0101504. 1 1
A WholeFarm Decision Support System for Preventive Integrated Pest Management and Nonpoint Source Pollution Control
, 1999
"... A decision support system for preventive integrated pest management (IPM) and nonpoint source (NPS) pollution control was designed, implemented and evaluated. The objective of the system was to generate plans at the farm level to satisfy economic and production goals while limiting risks of insect p ..."
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A decision support system for preventive integrated pest management (IPM) and nonpoint source (NPS) pollution control was designed, implemented and evaluated. The objective of the system was to generate plans at the farm level to satisfy economic and production goals while limiting risks of insect pest outbreaks, nitrate and pesticide leaching and runoff, and soil erosion. The system is composed of a constraint satisfaction planner (CROPSLT), a modified version of CROPS (Stone, 1995), a farmlevel resource management system (FLAME), an NPS module, which includes a weather generator, CLIGEN (Nicks et al. 1995), and an NPS distributedparameter model, ANSWERS (Bouraoui, 1994), databases, a database engine and utility programs. The performance of the system was analyzed and performance enhancing features were added to increase the planner's ability to find nearoptimal plans within a limited planning time. Using heuristics to sort potential crop rotations based on profit generally improved the planner's performance, as did removal of fields that were not suitable for growing target crops. Not surprisingly, the planner was best able to find plans for crops that can be grown in a variety of rotational systems. Throughout, the ability to apply environmental constraints selectively to individual fields greatly improved the planner's ability to find acceptable plans. Preventive IPM (PIPM) heuristics to control corn rootworms CRW (Diabrotica virgifera virgifera and D. barberi) were added to the planner. The model was represented and solved as a constraint satisfaction problem. Results indicated that plans obtained using PIPM heuristics had less risk of CRW damage, reduced chemical control costs, higher profit and reduced soil erosion as compared to a control plan. Linking the ...
unknown title
"... Abstract: There are large numbers of real life problems for which there is no any optimization algorithm which can solve such kinds of problems in the polynomial time in the worst case. So researchers are designing new approximation algorithms for such kinds of problems. Approximation algorithms giv ..."
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Abstract: There are large numbers of real life problems for which there is no any optimization algorithm which can solve such kinds of problems in the polynomial time in the worst case. So researchers are designing new approximation algorithms for such kinds of problems. Approximation algorithms gives the solution which is close to the optimal solution of a particular problem. In this paper, a study on Traveling Salesman problem is being done along with the difference in the time complexities of approximation algorithm as given by different researchers and an approximation algorithm is designed for traveling salesman problem. After analysis of time complexities of approximation algorithms, it is found that Researchers are continuously applying their best efforts to design new approximation algorithms which have less time complexity and space complexity as compared to the previously existing algorithms.
In Encylopedia of Electrical and Electronic Engineering, John Wiley and Sons. Data Structures and Algorithms
"... In this article we provide an introduction to data structures and algorithms. We consider some basic data structures and deal with implementations of a dictionary and a priority queue. Algorithms for such basic problems as matrix multiplication, binary search, sorting, and selection are given. The c ..."
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In this article we provide an introduction to data structures and algorithms. We consider some basic data structures and deal with implementations of a dictionary and a priority queue. Algorithms for such basic problems as matrix multiplication, binary search, sorting, and selection are given. The concepts of randomized computing and parallel computing are also visited. 1