Showing papers on "Sorting published in 1991"

The dynamics of collective sorting robot-like ants and ant-like robots

Abstract: A distributed sorting algorithm, inspired by how ant colonies sort their brood is presented for use by robot teams The robots move randomly, do not communicate have no hierarchical organisation, have no global representation can only perceive objects just in front of them, but can distinguish between objects of two or more types with a certain degree of error The probability that they pick up or put down an object is modulated as a function of how many of the same objects they have met in the recent past This generates a positive feed-back that is sufficient to coordinate the robots' activity, resulting in their sorting the objects into common clusters While less efficient than a hierarchically controlled sorting, this decentralised organisation offers the advantages of simplicity, flexibility and robustness

A comparison of sorting algorithms for the connection machine CM-2

Abstract: Sorting is arguably the most studied problem in computer science, both because it is used as a substep in many applications and because it is a simple, combinatorial problem with many interesting and diverse solutions. Sorting is also an important benchmark for parallel supercomputers. It requires significant communication bandwidth among processors, unlike many other supercomputer benchmarks, and the most efficient sorting algorithms communicate data in irregular patterns. Parallel algorithms for sorting have been studied since at least the 1960’s. An early advance in parallel sorting came in 1968 when Batcher discovered the elegant U(lg2 n)-depth bitonic sorting network [3]. For certain families of fixed interconnection networks, such as the hypercube and shuffle-exchange, Batcher’s bitonic sorting technique provides a parallel algorithm for sorting n numbers in U(lg2 n) time with n processors. The question of existence of a o(lg2 n)-depth sorting network remained open until 1983, when Ajtai, Komlos, and Szemeredi [1] provided an optimal U(lg n)-depth sorting network, but unfortunately, their construction leads to larger networks than those given by bitonic sort for all “practical” values of n. Leighton [15] has shown that any U(lg n)-depth family of sorting networks can be used to sort n numbers in U(lg n) time in the bounded-degree fixed interconnection network domain. Not surprisingly, the optimal U(lg n)-time fixed interconnection sorting networks implied by the AKS construction are also impractical. In 1983, Reif and Valiant proposed a more practical O(lg n)-time randomized algorithm for sorting [19], called flashsort. Many other parallel sorting algorithms have been proposed in the literature, including parallel versions of radix sort and quicksort [5], a variant of quicksort called hyperquicksort [23], smoothsort [18], column sort [15], Nassimi and Sahni’s sort [17], and parallel merge sort [6]. This paper reports the findings of a project undertaken at Thinking Machines Corporation to develop a fast sorting algorithm for the Connection Machine Supercomputer model CM-2. The primary goals of this project were:

A close neighbour algorithm for designing cellular manufacturing systems

Abstract: The first step in creating a cellular manufacturing system is to identify machine groups and form part families. Clustering and data organization (CDR) algorithms (such as the bond energy algorithm) and array sorting (ARS) methods (such as the rank order clustering algorithm) have been proposed to solve the machine and part grouping problem. However, these methods do not always produce a solution matrix that has a block diagonal structure, making visual identification of machine groups and part families extremely difficult. This paper presents a ‘close neighbour algorithm’ to solve this problem. The algorithm overcomes many deficiencies of the CDR and ASM methods. The algorithm is tested against ten existing algorithms in solving test problems from the literature. Test results show that the algorithm is very reliable and efficient.

Parallel sorting on a shared-nothing architecture using probabilistic splitting

Abstract: The authors consider the problem of external sorting in a shared-nothing multiprocessor. A critical step in the algorithms the authors consider is to determine the range of sort keys to be handled by each processor. They consider two techniques for determining these ranges of sort keys: exact splitting, using a parallel version of the algorithm proposed by Iyer, Ricard, and Varman; and probabilistic splitting, which uses sampling to estimate quantiles. They present analytic results showing that probabilistic splitting performs better than exact splitting. Finally, the authors present experimental results from an implementation of sorting probabilistic splitting in the Gamma parallel database machine. >

Age‐related Asynchrony of Knowledge and Action

Abstract: Children's ability to act in accordance with rules was assessed in 2 experiments. Experiment I included 66 children, aged 31, 33.5, or 36 months, who performed 2 tasks. In a forced-choice, deductive sorting task, children were told 2 rules (if-then statements) and then required to use the rules to sort items. A knowledge task tested children's knowledge about which rule's antecedent condition held true for each item. Rules were either based on natural categories (e.g., vehicles vs. musical instruments) or ad hoc categories (e.g., things found inside the house vs. things found outside). Children in the 2 younger age groups performed better on the knowledge task than on the sorting task. The 36-month-olds performed equally well on both tasks. In Experiment 2, groups of 12 32.25-month-olds received either the knowledge task, the sorting task, or a mnemonically supported version of the sorting task. The group that received the knowledge task performed better than the other groups, which did not differ. This result undermines the possibility that differential performance on the knowledge and sorting tasks is due to a difference in memory demand. Taken together, the results of Experiments 1 and 2 imply a relatively rapid, age-related change culminating in the ability to execute systematically rules that require access to extant knowledge.

A general sequential time-space tradeoff for finding unique elements

Abstract: An optimal $\Omega (n^2 )$ lower bound is shown for the time-space product of any R branching program that determines those values which occur exactly once in a list of n integers in the range $[1,R]$ where $R \geqq n$. This $\Omega (n^2 )$ tradeoff also applies to the sorting problem and thus improves the previous time-space tradeoffs for sorting. Because the R-way branching program is such a powerful model, these time-space product tradeoffs also apply to all models of sequential computation that have a fair measure of space such as off-line multitape Turing machines and off-line log-cost random access machines (RAMs).

Sorting a table by rows or columns in response to interactive prompting with a dialog box graphical icon

Abstract: An improved apparatus and method for sorting of information in a computerized spreadsheet or the like. The improved system provides for display of a graphical indication in the form of an icon indicative of the sort type, either by rows or by columns, which the data will be sorted in when a sort operation is performed.

Concentrated regular data streams on grids: sorting and routing near to the bisection bound

Abstract: Sorting and routing on r-dimensional n*. . .*n grids of processors is studied. Deterministic algorithms are presented for h-h problems, h>or=1, where each processor initially and finally contains h elements. It is shown that the classical 1-1 sorting can be solved with (2r-1.5)n+o(n) transport steps, i.e. in about 2.5n steps for r=2. The general h-h sorting problem, h>or=4r-4 can be solved within a number of transport steps that asymptotically differs by a factor of at most 3 from the trivial bisection bound. Furthermore, the bisection bound is asymptotically tight for sequences of h permutation routing problems, h=4cr, c>or=1, and for so-called offline routing. >

Flow Cytometry and Sorting

Abstract: Flow cytometry offers important advantages for the study of tumour cell biology. In particular, this powerful technique allows the identification of cell subpopulations within heterogeneous cell samples and permits simultaneous measurement and correlation of multiple cellular parameters. The explosion in flow cytometric analysis since 1979 when the first edition of 'Flow Cytometry and Sorting' was published, is reflected by the sheer size and weight and the small print used in this long awaited Second Edition! It is clearly not intended as 'an easy to follow' introduction to Flow Cytometry, however all established flow cytometry laboratories should certainly replace their now far outdated first edition. In order to follow Flow Cytometry and Sorting in its entirity the reader would need a working knowledge of at least physics, engineering, and computer science, together with fluorescence techniques and biochemistry and immunology! This edition is ambitious, comprising 39 chapters written by 70 authors expert in their area of flow cytometry. The chapters are divided into eight parts. Each chapter has been for the most part rewritten, and there are several additional

Large-scale sorting in parallel memories (extended abstract)

Abstract: We present several algorithms for sorting efficiently with parallel two-level and multilevel memories. Our main result is an elegant, easy-toimplement, optimal, deterministic algorithm for external sorting with P disk drives. This result answers the open problem posed by Vitter and Shriver. Our measure of performance is the number of parallel input/output (1/0) operations, in which each of the P disks can simultaneously transfer a block of B contiguous records. Our optimal algorithm is deterministic, and thus it improves upon the optimal randomized algorithm of [ViS] as well as the well-known deterministic but nonoptimal technique of disk striping. The second part of the paper broadens our coverage from two-level memories to more general multilevel memories. In particular we consider the blocked uniform memory hierarchy (UMH) introduced by Alpern, Carter, and Feig, and its parallelization P-UMH, along with new variants. We give optimal and nearly-optimal algorithms for a wide range of bandwidth degradations, including a parsimonious algorithm for constant bandwidth. We also develop optimal sorting algorithms for all bandwidths for other versions of UMH and P-UMH, including natural restrictions we intro* Support was provided in part by an IBM Graduate Fellowship and by a National Science Foundation Presidential Young Investigator Award CCR–9047466 with matching funds from IBM Corporation. t Support was provided in part by a National Science Foundation Presidential Young Investigator Award CCR-9047466 with matching funds from IBM Corporation, by National Science Fosmdation grant CCR-9007851, by the U.S. Army Research Office under grant DAAL03–91–G-o035, and by the Office of Naval Research and the Defense Advanced Research Projects Agency uader contract NOO014-83-K–0146 and ARPA order 6320, amendment 1. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the ACM copytight notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association for Computing Machinery. To copy otherwise, or to republish, requires a fee andlor specific permission. @ 1991 ACM 089791-438-4/91/000710029 $1.50 duce called RUMH and P-RUMH, which more closely correspond to current programming languages.

Microfabricated device for biological cell sorting

Abstract: Apparatus for sorting cells into spatially separate sub-groups, comprising a microfabricated moveable structure (4, 5, 6) for directing cells between distinct spatial locations.

Randomized sorting and selection on mesh-connected processor arrays (preliminary version)

Abstract: We show that sorting an input of size N = 0 2 can be performed by an 0 X 0 mesh-connected processor array in 2.50 +o(0) parallel communication steps and using constant size queues, with high probability. The best previously known algorithm for this problem required 30 +o(0) steps. We also show that selecting the element of rank k out of N = 0 2 inputs on an 0 X 0 mesh can be performed in 1.250 + 0(0) steps and using constant size queues, with high probability. The best previously known algorithm for this problem involved sorting, and required 30 +0(0) steps. Both of our algorithms can be generalized to higher dimensions, achieving bounds better than the known results. 1Aiken Computation Laboratory, Harvard University, Cambridge, MA 02138. 'Dept. of Computer Science, University of Rochester, Rochester, NY 14627. "Dept. of Computer Science, University of Rochester, Rochester, NY 14627. 'Dept. of Computer Science, Columbia University, New York, NY 10027.

Data processing system for optimized mail piece sorting and mapping to carrier walk sequence using real time statistical data

Abstract: A data processing system, method and program are disclosed to optimize mail piece sorting and the mapping of mail down to the carrier walk sequence using real time statistical data. The invention makes use of techniques such as fast OCR devices at a sending location or deferred processing of OCR scanned mail, to accumulate volume statistics indicating the number of mail pieces being routed particular addressees at a destination postal region on a given day. The information for mail volumes being directed to a particular postal region are collected over data communications links prior to the receipt of the actual mail pieces. The efficiency of sorting is maximized at the destination postal region by organizing the sorting apparatus to remove the highest volume addressee's mail first. This requires the compilation of the real time volume statistics from all of the sending postal regions sending mail to the destination postal location. In this manner, the maximum number of letters on every pass through the sorting apparatus can be achieved at the destination location. This minimizes the total number of reading operations required in order to achieve a desired level of mail sorting separation. Because the mail volume statistics are available at the destination location prior to sorting, at each stage of the sorting operations, bin allocation can be customized to yield the highest final patron or addressee sort. In this manner, the time for every subsequent pass through the sorting apparatus is reduced. This enables sorting directly to the addressee level and the distribution of the mail down to carrier walk sequence.

Method and apparatus for merging sorted lists in a multiprocessor shared memory system

Abstract: A system and method for merging a plurality of sorted lists using multiple processors having access to a common memory in which N sorted lists which may exceed the capacity of the common memory are merged in a parallel environment. Sorted lists from a storage device are loaded into common memory and are divided into a number of tasks equal to the number of available processors. The records assigned to each task are separately sorted, and used to form a single sorted list. A multi-processing environment takes advantage of its organization during the creation of the tasks, as well as during the actual sorting of the tasks.

Data edge phase sorting circuits

Abstract: Data edge phase sorting circuits for communication systems and information and data processing systems employing digital phase locked logic circuits. The sorting circuits phase sort edge transitions of a serial data stream relative to a local clock signal. The local clock signal is coupled to a delay line having a plurality of serially connected delay elements, each of which outputs a delay clock of different phase. The sorting circuit includes an extraction circuit coupled to receive the serial data stream for detecting edge transitions in the serial stream and outputting a pulse of predefined duration in response to each detected transition. Coupled to the extraction circuit output is a non-sequential logic circuit, which is also coupled to the local clock through the delay line. The non-sequential logic circuit combines the outputted extraction circuit pulse and the plurality of delay clocks for sorting the pulse relative to the delay clocks. Specific embodiments for the extraction circuit and non-sequential logic circuitry are depicted and described herein.

Computerized directory pagination system and method

Abstract: A fully automatic computerized pagination system and method for paginating printed directories is provided. The system and method use a computer process which comprises a sequence of sorting operations which sort and position the entry items based on specific parameters relating to the size, shape, type and page format directory rules. The sorting operations are performed on the input data automatically and in sequential phases of a programmed sequence, so that when the operations are finished an entire paginated directory is produced.

Sorting Out the Self-Esteem Controversy.

Abstract: The idea of enhancing self-esteem seems innocent enough to most people. Common sense suggests that those who have positive self-esteem are likely to lead satisfying lives while those who do not are just as likely to find life dissatisfying and unhappy. Yet. like so many other seemingly commonsensical things, the idea of self-es teem has become a source of consider able controversy and contention in the school context. So it is that, as we enter the 1990s, another \"great debate\" is emerging. This one is about whether schools ought to try to enhance selfesteem and, if so. how, on what grounds, and to what extent? That the school might play a role in the development of self-esteem is not a recent idea. It has been part of educa tional thinking for most of this century, particularly since the 1960s, when many educators came to realize that affect in general and self-esteem specifically loom large in school life. 1 But it \\*as in the 1980s that self-esteem was catapult ed into educational policy thinking. It became linked not only to academic achievement but also to substance abuse, antisocial acts, adolescent preg nancy, suicide, and other self-destruc tive behaviors. The theory was this: people, including the young, will not hurt themselves if they like themselves. Moreover, if they have self-confidence, they are more likely to do well at what ever they might try to do. This theory has driven many states and school districts to add development of self-esteem to their list of goals. It also served as the underlying theme of the notorious California self-esteem project that simultaneously appealed to the most humane impulses of some while offending the Puritan streak of self-denial that still runs deep in the values of others.Meanwhile, in the schools, the terrain is cluttered with conflicting and contradictory theories about self-esteem and ways to enhance it. The purpose of this article is to sort out this \"mess\" and to make some sense out of the idea of enhancing selfesteem in schools.

Transport carrier for use in an article sorting system

Abstract: A sorting system in which uniquely coded garments are hung on transport carriers, also having unique identification bar codes The garment transport carriers include a connector for removably attaching garments or garment hangers and a hook which engages the transport rails so that the carrier can be moved along the rails and throughout the sorting system Such a hook is used with slick-type rails, screw-type conveyor rails and even channel-type rails, or a rotatable wheel may be mounted on the carrier for movement of the carrier along rails, including channel-type rails The transport carrier bar code is read as it progresses through the sorting system and is compared with a computer data base of garment information to determine the sorting route The garment identification is initially correlated in the computer data base before sorting with the carrier identification code Once all garment carriers and associated garments of a lot have been identified and correlated by the computer, an algorithm is carried out for assigning a sort value to each carrier A master distributor switch then distributes the garment carriers a first time to a plurality of sort paths based upon a least significant digit of the sort value Second and subsequent digits of the sort value of each carrier are employed to recirculate and resort the garment carriers to the plural sort paths to complete the sorting operation with the parallel paths The garment carriers are then sequentially released from the parallel sort paths to an exit sort path in a final serial order representative of the order of the garments desired by the customers

Sorting for Polyhedron Compositing

Abstract: There are basically two ways to visualize a scalar function in a volume: (1) draw contour surfaces, or (2) integrate a continuous volume density along viewing rays. The polyhedron compositing scheme of Max, Hanrahan, and Crawfis [9] combines both of these techniques by subdividing the volume cells at contour surfaces, and compositing the resulting polyhedral pieces and surface polygons in back-to-front order. The application of this algorithm to two specific situations is described, each using a special back-to-front sorting method. One application uses hierarchical data resulting from adaptive mesh refinement, and the other uses cloud data from climate simulations.

Coping with erroneous information while sorting

Abstract: The authors study the problem of sorting n distinct elements in ascending sequence according to a total order, using comparison queries which receive 'yes' or 'no' answers, but of which as many as e may be erroneous. In a half-lie version, all 'yes' answers are guaranteed to be correct and the errors are confined to 'no' answers. It is shown that the comparison query complexity of the sorting problem for this case is Omega (n log n+e), and an asymptotically optimal algorithm is demonstrated. In a full-lie version, both 'yes' and 'no' answers can be false. It is shown that the comparison query complexity of the sorting problem for this case is Omega (n log n+en). >

Counting and cutting cycles of lines and rods in space

Abstract: A number of rendering algorithms in computer graphics sort three-dimensional objects by depth and assume that there is no cycle that makes the sorting impossible. One way to resolve the problem caused by cycles is to cut the objects into smaller pieces. The problem of estimating how many such cuts are always sufficient is addressed. A few related algorithmic and combinatorial geometry problems are considered. >

Scalability of parallel sorting on mesh multicomputers

Abstract: The paper presents two new parallel algorithms QSP1 and QSP2 based on sequential quicksort for sorting data on a mesh multicomputer, and analyzes their scalability using the isoefficiency metric. It shows that QSP2 matches the lower bound on the isoefficiency function for mesh multicomputers. The isoefficiency of QSP1 is also fairly close to optimal. Lang et al. (1985) and Schnorr et al. (1986) have developed parallel sorting algorithms for the mesh architecture that have either optimal (Schnorr) or close to optimal (Lang) run-time complexity for the one-element-per-processor case. Both QSP1 and QSP2 have worse performance than these algorithms for the one-element-per-processor case. But QSP1 and QSP2 have better scalability than the scaled-down variants of these algorithms (for the case in which there are more elements than processors). As a result, the new parallel formulations are better than these scaled-down variants in terms of speedup w.r.t the best sequential algorithms. The paper also presents a different variant of Lang's sort which is asymptotically as scalable as QSP2 (for the multiple-element-per-processor case). It briefly discusses another metric called 'resource consumption metric'. According to this metric, both QSP1 and QSP2 are strictly superior to Lang's sort and its variations. >

Multidimensional Scaling of Sorting Data: A Comparison of Three Procedures

Abstract: Dissimilarity measures (D) derived from sortings of stimuli can be submitted to multidimensional scaling (MDS) either directly, or after transforming them to profile distances (Δ) computed on the rows of the D matrix. The latter procedure was criticized by Drasgow and Jones (1979) who performed two simulation studies, which are criticized here in turn. In the present article two sets of real sorting data were used for comparing the results of MDS on D and Δ, both with each other and with the results of two other procedures: multiple correspondence analysis (by means of HOMALS) on the raw sorting data, and MDS on the pairwise similarity ratings of the same stimuli by the same subjects. The three procedures were compared both with respect to the final configurations and with regard to the fit of the corresponding distances to the data. These comparisons suggested that MDS on D is slightly superior to MDS on Δ. The latter analysis, however, yields results that are similar to those of the much more efficient HOMALS program. The differences, however, are on the average very small.