Johns Hopkins University Department of Computer Science
Overview
Works:  86 works in 87 publications in 1 language and 91 library holdings 

Publication Timeline
.
Most widely held works by
Johns Hopkins University
The bisector of a point and a plane parametric curve by
Rida A. M. T Farouki(
Book
)
1 edition published in 1991 in English and held by 2 WorldCat member libraries worldwide
Abstract: "The bisector of a fixed point p and a smooth plane curve C  i.e., the locus traced by a point that remains equidistant with respect to p and C  is investigated in the case that C admits a regular polynomial or rational parameterization. It is shown that the bisector may be regarded as (a subset of) a 'variabledistance' offset curve to C which has the attractive property, unlike fixeddistance offsets, of being generically a rational curve. This 'untrimmed bisector' usually exhibits irregular points and selfintersections similar in nature to those seen on fixeddistance offsets. A trimming procedure, which identifies the parametric subsegments of this curve that constitute the true bisector, is described in detail. The bisector of the point p and any finite segment of the curve C is also discussed."
1 edition published in 1991 in English and held by 2 WorldCat member libraries worldwide
Abstract: "The bisector of a fixed point p and a smooth plane curve C  i.e., the locus traced by a point that remains equidistant with respect to p and C  is investigated in the case that C admits a regular polynomial or rational parameterization. It is shown that the bisector may be regarded as (a subset of) a 'variabledistance' offset curve to C which has the attractive property, unlike fixeddistance offsets, of being generically a rational curve. This 'untrimmed bisector' usually exhibits irregular points and selfintersections similar in nature to those seen on fixeddistance offsets. A trimming procedure, which identifies the parametric subsegments of this curve that constitute the true bisector, is described in detail. The bisector of the point p and any finite segment of the curve C is also discussed."
Sorting on a parallel pointer machine with applications to set expression evaluation by
Michael T Goodrich(
Book
)
2 editions published between 1989 and 1991 in English and held by 2 WorldCat member libraries worldwide
Abstract: "We present algorithms for sorting on parallel CREW and EREW versions of the pointer machine model. Intuitively, one can view our methods as being based on the use of linked lists rather than arrays (the usual parallel data structure). Our results show the existence of simple sorting algorithms for models that are weaker than the PRAM models used in Cole's sorting algorithms. We also show how to exploit the 'locality' of our approach to generalize our sorting algorithms to solve a problem with applications to database querying and logic programming (setexpression evaluation) in O(log n) time using O(n) processors. Interestingly, this is an asymptotic improvement over what seems possible using previous techniques."
2 editions published between 1989 and 1991 in English and held by 2 WorldCat member libraries worldwide
Abstract: "We present algorithms for sorting on parallel CREW and EREW versions of the pointer machine model. Intuitively, one can view our methods as being based on the use of linked lists rather than arrays (the usual parallel data structure). Our results show the existence of simple sorting algorithms for models that are weaker than the PRAM models used in Cole's sorting algorithms. We also show how to exploit the 'locality' of our approach to generalize our sorting algorithms to solve a problem with applications to database querying and logic programming (setexpression evaluation) in O(log n) time using O(n) processors. Interestingly, this is an asymptotic improvement over what seems possible using previous techniques."
A comparison of three hidden line removal algorithms by Larry B Hostetler(
Book
)
1 edition published in 1989 in English and held by 2 WorldCat member libraries worldwide
Abstract: "Three algorithms for hidden line removal by Devai [4], Goodrich [6], and Schmitt [8], are compared on the basis of their execution times over a test set of schemes to be displayed."
1 edition published in 1989 in English and held by 2 WorldCat member libraries worldwide
Abstract: "Three algorithms for hidden line removal by Devai [4], Goodrich [6], and Schmitt [8], are compared on the basis of their execution times over a test set of schemes to be displayed."
Outputsensitive hidden surface elimination for rectangles by
Mikhail J Atallah(
Book
)
1 edition published in 1988 in English and held by 2 WorldCat member libraries worldwide
Abstract: "We present an algorithm for the wellknown hiddensurface elimination problem for rectangles, which is also known as the window rendering problem. The time complexity of our algorithm is sensitive to the size of the output. Specifically, it runs in time that is O (n [superscript 1.5] + k), where k is the size of the output (which can be as large as [theta] (n [squared])). For values of k in the range between n [superscript 1.5] / log n and n [squared], our algorithm is asymptotically faster than previous ones."
1 edition published in 1988 in English and held by 2 WorldCat member libraries worldwide
Abstract: "We present an algorithm for the wellknown hiddensurface elimination problem for rectangles, which is also known as the window rendering problem. The time complexity of our algorithm is sensitive to the size of the output. Specifically, it runs in time that is O (n [superscript 1.5] + k), where k is the size of the output (which can be as large as [theta] (n [squared])). For values of k in the range between n [superscript 1.5] / log n and n [squared], our algorithm is asymptotically faster than previous ones."
Computing the center of area of a simple polygon by Matthew Daz(
Book
)
1 edition published in 1989 in English and held by 2 WorldCat member libraries worldwide
For orthogonal nonconvex polygons, our algorithm runs in O(nGK), and for nonconvex polygons the time complexity is O(n⁴log nGK + nGK + nGK)."
1 edition published in 1989 in English and held by 2 WorldCat member libraries worldwide
For orthogonal nonconvex polygons, our algorithm runs in O(nGK), and for nonconvex polygons the time complexity is O(n⁴log nGK + nGK + nGK)."
Outputsensitive methods for rectilinear hidden surface removal by
Michael T Goodrich(
Book
)
1 edition published in 1990 in English and held by 2 WorldCat member libraries worldwide
Abstract: "We present an algorithm for the hiddensurface elimination problem for rectangles, which is also known as window rendering. The time complexity of our algorithm is dependent on both the number of input rectangles, n, and on the size of the output, k. Our algorithm obtains a tradeoff between these two components, in that its running time is [formula], where 1<=r<=log n is a tunable parameter. By using this method while adjusting the parameter r "on the fly" one can achieve a running time that is [formula]. Note that when k is theda(n), this achieves an O(n log n) running time, and when k is [formula] for any positive constant e, then this achieves an O(k) running time both of which are optimal."
1 edition published in 1990 in English and held by 2 WorldCat member libraries worldwide
Abstract: "We present an algorithm for the hiddensurface elimination problem for rectangles, which is also known as window rendering. The time complexity of our algorithm is dependent on both the number of input rectangles, n, and on the size of the output, k. Our algorithm obtains a tradeoff between these two components, in that its running time is [formula], where 1<=r<=log n is a tunable parameter. By using this method while adjusting the parameter r "on the fly" one can achieve a running time that is [formula]. Note that when k is theda(n), this achieves an O(n log n) running time, and when k is [formula] for any positive constant e, then this achieves an O(k) running time both of which are optimal."
Algorithms for computing the center of area of a convex polygon by Matthew Daz(
Book
)
1 edition published in 1988 in English and held by 1 WorldCat member library worldwide
Abstract: "Given a convex polygon P, associate with each point p [is a member of] P the minimum area of the polygon to the left of any chord through p. The maximum over all points in P is known as 'Winternitz's Measure of Symmetry' and the point p[superscript *] that achieves this maximum we call the center of area. We will show that p[superscript *] is unique and derive geometric properties of minimumarea chords. These properties lead to two algorithms for computing the center of area of a convex polygon with n vertices. The first is a combinatorial algorithm that runs in time O(n[superscript 6]log[superscript 2]n). The second in a numerical algorithm that computes the coordinates to K bits of precision in time O(nK). We conclude with a discussion of our implementation of the second algorithm, extensions to higher dimensions and other generalizations."
1 edition published in 1988 in English and held by 1 WorldCat member library worldwide
Abstract: "Given a convex polygon P, associate with each point p [is a member of] P the minimum area of the polygon to the left of any chord through p. The maximum over all points in P is known as 'Winternitz's Measure of Symmetry' and the point p[superscript *] that achieves this maximum we call the center of area. We will show that p[superscript *] is unique and derive geometric properties of minimumarea chords. These properties lead to two algorithms for computing the center of area of a convex polygon with n vertices. The first is a combinatorial algorithm that runs in time O(n[superscript 6]log[superscript 2]n). The second in a numerical algorithm that computes the coordinates to K bits of precision in time O(nK). We conclude with a discussion of our implementation of the second algorithm, extensions to higher dimensions and other generalizations."
A comparison of learning methods that use geometric primitives by
Steven L Salzberg(
Book
)
1 edition published in 1991 in English and held by 1 WorldCat member library worldwide
Abstract: "This paper compares four inductive learning techniques that employ geometric primitives for their generalization processes. A geometric primitive is any simple geometric object, such as a line or a circle, that may be used to build concept descriptions. Each method learns from examples, where an example consists of a vector of realvalued features plus a label. The learning problem is to produce a model that correctly assigns labels to new examples in the feature space. Our experiments show that, although the methods have various conceptual features that are in each case desirable, experimental performance does not clearly favor any of them
1 edition published in 1991 in English and held by 1 WorldCat member library worldwide
Abstract: "This paper compares four inductive learning techniques that employ geometric primitives for their generalization processes. A geometric primitive is any simple geometric object, such as a line or a circle, that may be used to build concept descriptions. Each method learns from examples, where an example consists of a vector of realvalued features plus a label. The learning problem is to produce a model that correctly assigns labels to new examples in the feature space. Our experiments show that, although the methods have various conceptual features that are in each case desirable, experimental performance does not clearly favor any of them
A polygonal approach to hiddenline elimination by
Michael T Goodrich(
Book
)
1 edition published in 1988 in English and held by 1 WorldCat member library worldwide
Abstract: "We present algorithms for the wellknown hiddenline and hiddensurface elimination problems. Our algorithms are optimal in the worst case, and are also able to take advantage of problem instances that are 'simpler' than in the worst case. Specifically, our algorithms run in O(n log n + k + t) time, where n is the number of edges, and k (resp. t) is the number of intersecting pairs of line segments (resp. polygons) in the projection plane [pi]. Our algorithms are based on a polygonbased strategy, rather than an edgebased strategy, and are quite simple."
1 edition published in 1988 in English and held by 1 WorldCat member library worldwide
Abstract: "We present algorithms for the wellknown hiddenline and hiddensurface elimination problems. Our algorithms are optimal in the worst case, and are also able to take advantage of problem instances that are 'simpler' than in the worst case. Specifically, our algorithms run in O(n log n + k + t) time, where n is the number of edges, and k (resp. t) is the number of intersecting pairs of line segments (resp. polygons) in the projection plane [pi]. Our algorithms are based on a polygonbased strategy, rather than an edgebased strategy, and are quite simple."
Dupin cyclides as blending surfaces for cones by
John K Johnstone(
Book
)
1 edition published in 1992 in English and held by 1 WorldCat member library worldwide
1 edition published in 1992 in English and held by 1 WorldCat member library worldwide
On the power of probabilistic polynomial time : (extended abstract) by
Richard Beigel(
Book
)
1 edition published in 1989 in English and held by 1 WorldCat member library worldwide
Abstract: "We show that probabilistic polynomial time is closed under polynomialtime parity reductions. Therefore every set polynomialtime truthtable reducible to SAT (every set in the [formula] level of the polynomial hierarchy) is accepted by a probabilistic polynomialtime Turing machine. Equivalently, [formula]."
1 edition published in 1989 in English and held by 1 WorldCat member library worldwide
Abstract: "We show that probabilistic polynomial time is closed under polynomialtime parity reductions. Therefore every set polynomialtime truthtable reducible to SAT (every set in the [formula] level of the polynomial hierarchy) is accepted by a probabilistic polynomialtime Turing machine. Equivalently, [formula]."
Merging free trees in parallel for efficient Voronoi diagram construction by Richard Cole(
Book
)
1 edition published in 1989 in English and held by 1 WorldCat member library worldwide
This structure facilitates the use of our fast merging procedure, for it allows the divideandconquer procedure to continue without needing to explicitly remove edges of recursively constructed diagrams that are not part of the final diagram. We use this approach to derive two results regarding the deterministic parallel construction of a Voronoi diagram. Specifically, we show that one can solve the Voronoi diagram in O(log n log log n) time and O(n logn) work (which improves the previous time bound while maintaining the same work bound) or, alternatively, in O(logn) time and O(n log n) work (which improves the previous work bound while maintaining the same time bound). Our model of computation is the CREW PRAM
1 edition published in 1989 in English and held by 1 WorldCat member library worldwide
This structure facilitates the use of our fast merging procedure, for it allows the divideandconquer procedure to continue without needing to explicitly remove edges of recursively constructed diagrams that are not part of the final diagram. We use this approach to derive two results regarding the deterministic parallel construction of a Voronoi diagram. Specifically, we show that one can solve the Voronoi diagram in O(log n log log n) time and O(n logn) work (which improves the previous time bound while maintaining the same work bound) or, alternatively, in O(logn) time and O(n log n) work (which improves the previous work bound while maintaining the same time bound). Our model of computation is the CREW PRAM
Inplace techniques for parallel convex hull algorithms by Mujtaba R Ghouse(
Book
)
1 edition published in 1991 in English and held by 1 WorldCat member library worldwide
1 edition published in 1991 in English and held by 1 WorldCat member library worldwide
A numerical method for rendering sphere reflections by
E. S Panduranga(
Book
)
1 edition published in 1989 in English and held by 1 WorldCat member library worldwide
This algorithm has exhibited many attractive properties, e.g., low computation cost, objectspaceoriented therefore resolution and device independence, etc. Moreover, it provides a guideline for future research interest, that it, it is quite likely to generalize this method to render reflections in a family of curved surfaces."
1 edition published in 1989 in English and held by 1 WorldCat member library worldwide
This algorithm has exhibited many attractive properties, e.g., low computation cost, objectspaceoriented therefore resolution and device independence, etc. Moreover, it provides a guideline for future research interest, that it, it is quite likely to generalize this method to render reflections in a family of curved surfaces."
Computing the intersection of a plane and a natural quadric by
John K Johnstone(
Book
)
1 edition published in 1991 in English and held by 1 WorldCat member library worldwide
Abstract: "A method of computing the intersection of a plane and a natural quadric surface is presented. This problem is basic in geometric areas such as solid modeling and descriptive geometry. Our method, arising out of recent work on lower degree intersections of quadrics, computes the directions of the axes of the intersection, and then computes their lengths using the Dandelin sphere. The method also gives all parallel plane sections of the natural quadric, with no added computation."
1 edition published in 1991 in English and held by 1 WorldCat member library worldwide
Abstract: "A method of computing the intersection of a plane and a natural quadric surface is presented. This problem is basic in geometric areas such as solid modeling and descriptive geometry. Our method, arising out of recent work on lower degree intersections of quadrics, computes the directions of the axes of the intersection, and then computes their lengths using the Dandelin sphere. The method also gives all parallel plane sections of the natural quadric, with no added computation."
Intersecting line segments in parallel with an outputsensitive number of processors by
Michael T Goodrich(
Book
)
1 edition published in 1988 in English and held by 1 WorldCat member library worldwide
The algorithm does not receive the value of k as input, it determines it online. We also show how to solve an important special case of the segment arrangement problem, namely, when each input segments is parallel to one of the coordinate axes (i.e., isooriented). Our algorithm for this problem runs in O(log n) time using an optimal O(n+k/log n) processors in the CREW PRAM model."
1 edition published in 1988 in English and held by 1 WorldCat member library worldwide
The algorithm does not receive the value of k as input, it determines it online. We also show how to solve an important special case of the segment arrangement problem, namely, when each input segments is parallel to one of the coordinate axes (i.e., isooriented). Our algorithm for this problem runs in O(log n) time using an optimal O(n+k/log n) processors in the CREW PRAM model."
Using certification trails to achieve software fault tolerance by
Gregory F Sullivan(
Book
)
1 edition published in 1989 in English and held by 1 WorldCat member library worldwide
Because of the availability of the certification trail, the second phase can be performed by a less complex program and can execute more quickly. In the final phase, the two results are compared and if they agree the results are accepted as correct; otherwise an error is indicated. An essential aspect of this approach is that the second program must always generate either an error indication or a correct output even when the certification trail it receives from the first program is incorrect
1 edition published in 1989 in English and held by 1 WorldCat member library worldwide
Because of the availability of the certification trail, the second phase can be performed by a less complex program and can execute more quickly. In the final phase, the two results are compared and if they agree the results are accepted as correct; otherwise an error is indicated. An essential aspect of this approach is that the second program must always generate either an error indication or a correct output even when the certification trail it receives from the first program is incorrect
Virtually defectfree code as a direct result of a welldefined comprehensive testing method by Phillis A Schneck(
Book
)
1 edition published in 1991 in English and held by 1 WorldCat member library worldwide
Abstract: "The upgrading and refinement of the test plans and processes currently used in the construction of large software systems makes the production of virtually defectfree code has [sic] become a reality. The primary purpose of this paper is to document and build the basis for a comprehensive approach to testing that has proven successful in developing and delivering defectfree code."
1 edition published in 1991 in English and held by 1 WorldCat member library worldwide
Abstract: "The upgrading and refinement of the test plans and processes currently used in the construction of large software systems makes the production of virtually defectfree code has [sic] become a reality. The primary purpose of this paper is to document and build the basis for a comprehensive approach to testing that has proven successful in developing and delivering defectfree code."
From operational to denotational semantics by Scott Fraser Smith(
Book
)
1 edition published in 1990 in English and held by 1 WorldCat member library worldwide
Abstract: "In this paper we directly prove certain basic theorems about an operational ordering [formula] on programs that normally are proved by defining a domain for the language. These basic theorems include congruence, least fixedpoint, continuity, and fixedpoint induction. We then show how any ordering on programs for which these basic theorems hold can be extended to give a fully abstract cpo for the language, giving a novel technique for generating these structures. The usefulness of this technique is illustrated by solving the open problem of finding a fully abstract semantics for the pure lazy lambdacalculus."
1 edition published in 1990 in English and held by 1 WorldCat member library worldwide
Abstract: "In this paper we directly prove certain basic theorems about an operational ordering [formula] on programs that normally are proved by defining a domain for the language. These basic theorems include congruence, least fixedpoint, continuity, and fixedpoint induction. We then show how any ordering on programs for which these basic theorems hold can be extended to give a fully abstract cpo for the language, giving a novel technique for generating these structures. The usefulness of this technique is illustrated by solving the open problem of finding a fully abstract semantics for the pure lazy lambdacalculus."
Constructing arrangements optimally in parallel by
Michael T Goodrich(
Book
)
1 edition published in 1990 in English and held by 1 WorldCat member library worldwide
1 edition published in 1990 in English and held by 1 WorldCat member library worldwide
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Related Identities
 Goodrich, Michael T. Author
 Johnstone, John K. Author
 Beigel, Richard Author
 Masson, Gerald M.
 Atallah, Mikhail J. Author
 Kosaraju, S. Rao Author
 Shene, ChingKuang Author
 O'Rourke, Joseph
 Salzberg, Steven L. 1960 Author
 Kasif, Simon Author
Associated Subjects
Algorithms Computational complexity Computational linguistics Computer graphics Computer software Cone Curves Data structures (Computer science) Faulttolerant computing Geometry GeometryData processing Lambda calculus Machine learning Parallel processing (Electronic computers) Polygons Polynomials Rectangles Software engineering Sorting (Electronic computers) Sphere Surfaces, Algebraic Voronoi polygons
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