This study was a qualitative analysis of introductory-level computer science students' comprehension of sorting algorithms. We asked six students to read and summarize the code of a sorting algorithm. Next, we ask...
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ISBN:
(纸本)9781450358903
This study was a qualitative analysis of introductory-level computer science students' comprehension of sorting algorithms. We asked six students to read and summarize the code of a sorting algorithm. Next, we asked them to trace through the code, first using a provided array with pencil and paper, then again using sticky-notes to represent the array. Focused analysis of one interview found that a student who struggled to comprehend the algorithm during the pencil-and-paper trace quickly gained understanding when physically tracing the sticky-note array. We hypothesize that physical interaction with a sticky-note representation of an array facilitated student comprehension of sorting algorithms by consolidating multiple lines of code (LOC) into a single repeatable action. This research is relevant to computer science educators who may teach sorting algorithms to introductory-level students.
This paper describes a fast integer sorting algorithm, herein referred to as Bit-index sort, which does not use comparisons and is intended to sort partial permutations. Experimental results exhibit linear complexity ...
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ISBN:
(纸本)9781467356138;9781467356121
This paper describes a fast integer sorting algorithm, herein referred to as Bit-index sort, which does not use comparisons and is intended to sort partial permutations. Experimental results exhibit linear complexity order in execution time. Bit-index sort uses a bit-array to classify input sequences of distinct integers, and exploits built-in bit functions in C compilers, supported by machine hardware, to retrieve the ordered output sequence. Results show that Bit-index sort outperforms quicksort and counting sort algorithms when compared in their execution time. A parallel approach for Bit-index sort using two simultaneous threads is also included, which obtains further speedups of up to 1.6 compared to its sequential case.
The Aircraft scheduling problem is researched in this paper, the equilibrium model of aircraft scheduling problem is proposed and a sorting algorithm is constructed. By introducing the concept of flight connections, a...
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ISBN:
(纸本)9783037855447
The Aircraft scheduling problem is researched in this paper, the equilibrium model of aircraft scheduling problem is proposed and a sorting algorithm is constructed. By introducing the concept of flight connections, aircraft scheduling problem is transformed into the distribution of flight connections, the mathematical model of the problem is established, to solve the model, a sorting algorithm is constructed. We use the airline's flight data to test the algorithm. The simulation results show that the model and the algorithm are feasible.
Following the footprints of what has been done with the algorithm Stacksort, we investigate the preimages of the map associated with a slightly less well known algorithm, called Queuesort. After having described an eq...
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Following the footprints of what has been done with the algorithm Stacksort, we investigate the preimages of the map associated with a slightly less well known algorithm, called Queuesort. After having described an equivalent version of Queuesort, we provide a recursive description of the set of all preimages of a given permutation, which can be also translated into a recursive procedure to effectively find such preimages. We then deal with some enumerative issues. More specifically, we investigate the cardinality of the set of preimages of a given permutation, showing that all cardinalities are possible, except for 3. We also give exact enumeration results for the number of permutations having 0,1 and 2 preimages. Finally, we consider the special case of those permutations pi whose set of left-to-right maxima is the disjoint union of a prefix and a suffix of pi: we determine a closed formula for the number of preimages of such permutations, which involves two different incarnations of ballot numbers, and we show that our formula can be expressed as a linear combination of Catalan numbers. (C) 2021 Elsevier B.V. All rights reserved.
sorting is one of the most important computational tasks in data processing applications. Recent studies show that the FPGA-based hardware accelerators are more efficient than the general-purpose processors and GPUs. ...
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ISBN:
(纸本)9781728127880
sorting is one of the most important computational tasks in data processing applications. Recent studies show that the FPGA-based hardware accelerators are more efficient than the general-purpose processors and GPUs. By increasing the input records in the sorting network, the number of Compare-And-Swap (CAS) units would be increased, which in turn, will lead to increased resource consumption. In some applications, the number of available resources is limited. Thereby, it is necessary to optimize resource requirements while maintaining a sufficient level of performance. This paper presents a new sorting architecture that reduces the number of required resources compared to the state-of-the-art sorting architecture and achieves the desired performance using Unary processing. Results indicate that the proposed architecture increases throughput by 29.1% and reduces the number of LUTs by 42%, for sorting 8-input records, compared to other architecture.
A gas source declaration scheme based on a tetrahedral sensor structure in three-dimensional airflow environments is proposed. First, a tetrahedral sensor structure was established. Based on the tetrahedral structure,...
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A gas source declaration scheme based on a tetrahedral sensor structure in three-dimensional airflow environments is proposed. First, a tetrahedral sensor structure was established. Based on the tetrahedral structure, the gas source declaration problem was converted into a two-class classification issue. Then a classification algorithm combining an extreme learning machine (ELM, a fast neural network classifier) with a gas mass flux criterion is proposed. A novel calculation method for the mass flux through a closed tetrahedral surface is presented, and a mass flux criterion was developed which acts as a training sample filter for the ELM. The source declaration scheme was validated by using both regular and irregular tetrahedron experiments. Published under license by AIP Publishing.
Polarimetric Synthetic Aperture Radar (PolSAR) images are an important source of information. Speckle noise gives SAR images a granular appearance that makes interpretation and analysis hard tasks. A major issue is th...
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Polarimetric Synthetic Aperture Radar (PolSAR) images are an important source of information. Speckle noise gives SAR images a granular appearance that makes interpretation and analysis hard tasks. A major issue is the assessment of information content in these kinds of images, and how it is affected by usual processing techniques. Previous works have resulted in various approaches for quantifying image information content. In this paper, we study this problem from the classification accuracy viewpoint, focusing on the filtering and the classification stages. Thus, through classified images, we verify how changing the properties of the input data affects their quality. The input is an actual PolSAR image, the control parameters are (i) the filter (Local Mean, LM, or Model-Based PolSAR, MBPolSAR) and the size of their support, and (ii) the classification method (Maximum Likelihood, ML, or Support Vector Machine, SVM), and the output is the precision of the classification algorithm applied to the filtered data. To expand the conclusions, this study deals not only with Classification Accuracy but also with Kappa and Overall Accuracy as measures of map precision. Experiments were conducted on two airborne PolSAR images. Differently from what was observed in previous works, almost all quality measures are good and increase with degradation, i.e. the filtering algorithms that we used always improve the classification results at least up to supports of size 7 x 7.
Orthogonal confirmation of next-generation sequencing (NGS)-detected germline variants is standard practice, although published studies have suggested that confirmation of the highest-quality calls may not always be n...
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Orthogonal confirmation of next-generation sequencing (NGS)-detected germline variants is standard practice, although published studies have suggested that confirmation of the highest-quality calls may not always be necessary. The key question is how Laboratories can establish criteria that consistently identify those NGS calls that require confirmation. Most prior studies addressing this question have had limitations: they have been generally of small scale, omitted statistical justification, and explored limited aspects of underlying data. The rigorous definition of criteria that separate high-accuracy NGS calls from those that may or may not be true remains a crucial issue. We analyzed five reference samples and over 80,000 patient specimens from two laboratories. Quality metrics were examined for approximately 200,000 NGS calls with orthogonal data, including 1662 false positives. A classification algorithm used these data to identify a battery of criteria that flag 100% of false positives as requiring confirmation (CI lower bound, 98.5% to 99.8%, depending on variant type) white minimizing the number of flagged true positives. These criteria identify false positives that the previously published criteria miss. Sampling analysis showed that smaller data sets resulted in less effective criteria. Our methodology for determining test- and laboratory-specific criteria can be generalized into a practical approach that can be used by laboratories to reduce the cost and time burdens of confirmation without affecting clinical accuracy.
Distributions of Monge type are a class of strongly regular bracket-generating distributions introduced by I. Anderson, Zh. Nie and P. Nurowski. Their symbol algebras prolong to simple graded Lie algebras, thus allowi...
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Distributions of Monge type are a class of strongly regular bracket-generating distributions introduced by I. Anderson, Zh. Nie and P. Nurowski. Their symbol algebras prolong to simple graded Lie algebras, thus allowing one to associate a parabolic geometry to any given Monge distribution. This article is devoted to the classification problem for homogeneous models of Monge distributions of type C-3 in dimension eight, and is complementary to a paper by I. Anderson and P. Nurowski. The general classification algorithm, as well as most of its application to the particular problem, are joint work with Ian Anderson. (C) 2018 Elsevier B.V. All rights reserved.
The existing laboratory methods have limitations that make it very difficult to select the most suitable method for obtaining precise permeability measurements for evaluating reservoir formation damage. To date, there...
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The existing laboratory methods have limitations that make it very difficult to select the most suitable method for obtaining precise permeability measurements for evaluating reservoir formation damage. To date, there has been no research critically addressing this issue. In this study, the permeabilities of core or cuttings samples taken from No.15 Reservoir in the Qinshui Basin before and after damage caused by drilling and fracturing fluids were randomly measured using six general laboratory methods. Their average permeability values, as well as the extent of absolute and relative formation damage, were calculated and analyzed using a simple ranking method, statistical screening algorithm, and theoretical method. The results show that, first, there is a regular distribution of absolute reservoir damage measured by the laboratory methods;and second, the application priority of permeability measurement methods for formation damage evaluation in coal bed methane reservoirs is as follows: cuttings pulse decay method > constant flow rate method > nuclear magnetic resonance method > plunger pulse decay method = pressure oscillation method = constant pressure method. The cuttings pulse decay method is therefore recommended for measuring core matrix damage, while the constant flow rate method is suggested for measuring overall damage to core samples.
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