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Cooperative Multiple Agent-Based Algorithm for Evacuation Planning for Victims with Different Urgencies

JOURNAL OF AEROSPACE INFORMATION SYSTEMS 2018年第6期15卷 382-395页

作者： Oh, Byung Hoon Kim, Kwangyeon Choi, Han-Lim Hwang, Inseok Purdue Univ Sch Aeronaut & Astronaut W Lafayette IN 47907 USA Korea Adv Inst Sci & Technol Dept Aerosp Engn Daejeon 305701 South Korea

A well-organized evacuation plan is crucial to save more lives in the aftermath of natural disasters. In this paper, a mathematical model and an efficient solution approach are proposed for optimal planning of a fleet of aerial vehicles to save victims with different levels of urgency. Evacuation planning is a task assignment problem combined with scheduling of aerial vehicles with different capabilities while considering complex conditions such as multiple bases for the vehicles, victims with different urgency levels at multiple locations, and multiple safe locations (for example, hospitals and refuges). In our previous work, the problem was formulated as integer linear programming to provide optimal solution. Because the integer linear programming, however, is intractable for a large-scale disaster problem, a heuristic method called the cooperative multiagent-based algorithm is proposed to solve the large-scale problem in practical time. The proposed algorithm defines simple rules for vehicle agents and demand agents (victims), and it applies cooperative interaction between agents to efficiently find a suboptimal solution. The computational efficiency and the performance of the algorithm are demonstrated using illustrative numerical examples based on realistic data.

关键词： Numerical algorithms Mathematical Models Helicopters Particle Swarm Optimization Federal Emergency Management Agency Unmanned Aerial Vehicle Aircraft Operations Genetic Algorithm Flight Vehicle sorting algorithms

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Sort race

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SOFTWARE-PRACTICE & EXPERIENCE 2022年第8期52卷 1867-1878页

作者： Zhang, Hantao Meng, Baoluo Liang, Yiwen Univ Iowa Dept Comp Sci Iowa City IA 52242 USA GE Res New York NY USA Wuhan Univ Dept Comp Sci Wuhan Hubei Peoples R China

sorting is one of the oldest computing problems and is still very important in the age of big data. Numerous algorithms and implementation techniques have been proposed. In this study, we focus on comparison based, internal sorting algorithms. We created 12 types of data of various sizes for experiments and tested extensively various implementations in a single setting. Using some effective techniques, we found that quicksort is adaptive to nearly sorted inputs and is still the best overall sorting algorithm. We also identified techniques that are effective in timsort, which is one of the most popular and efficient sorting methods based on natural mergesort. In addition, we created a version of our own mergesort, which performs better than timsort on nearly sorted instances. Our implementations of quicksort and mergesort are different from other implementations reported in all textbooks or research articles, and are faster than any version of the C library qsort functions not only for randomly generated data, but also for various types of nearly sorted data. This work can aid the user to choose the best sorting algorithm for the hard sorting job at hand, and provides a platform for anyone to test their own sorting algorithm against the best in the field.

关键词： merge sort quick sort sorting algorithms

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AN EMPIRICAL-STUDY OF THE RUN-TIME BEHAVIOR OF QUICKSORT, SHELLSORT AND MERGESORT FOR MEDIUM TO LARGE-SIZE DATA

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COMPUTER LANGUAGES 1994年第2期20卷 127-134页

作者： SARWAR, SM JARAGH, MHA WIND, M KUWAIT UNIV FAC ENGN & PETRDEPT ELECT & COMP ENGNSAFAT 13060KUWAIT

The paper describes the results of a large empirical study to measure the practical behavior of the basic versions of the popular internal sorting algorithms, Shellsort, quicksort, and mergesort, for medium to large size data and compares them with previous results. The results give running times of theta (N1.25) for Shellsort, quicksort, and mergesort for 1000 < N < 2 x 10(6). The study also shows that Shellsort behaves better than mergesort for 1000 < N < 150,000. However, mergesort outperforms Shellsort for N > 150,000. Quicksort outperforms both Shellsort and mergesort for all values of N > 1000. Our fits show better performance for Shellsort than the previous studies and are mostly accurate to within 2% for 1000 < N < 2 x 10(6). The primary reason for this error seems to be related to the error in the measured data.

关键词： PERFORMANCE EVALUATION sorting algorithms QUICKSORT SHELLSORT MERGESORT

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PARALLEL MERGING - ALGORITHM AND IMPLEMENTATION RESULTS

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PARALLEL COMPUTING 1990年第1-3期15卷 165-177页

作者： VARMAN, PJ IYER, BR HADERLE, DJ DUNN, SM IBM CORP ALMADEN RES CTRINST DATABASE TECHNOLSAN JOSECA 95120

An efficient parallel algorithm for merging two sorted lists is presented. The algorithm is based on a novel partitioning algorithm that splits the two lists among the processors, in a way that ensures load balance during the merge. The partitioning algorithm can itself be efficiently parallelized, allowing the solution to scale with increased numbers of processors. A shared memory multiprocessor is assumed. The time complexity for partitioning and merging is O(N/p + log N), where p is the number of processors and N is the total number of elements in the two lists. Implementation results on a twenty node Sequent Symmetry multiprocessor are also presented.

关键词： sorting algorithms Parallel merging Shared memory multiprocessor Complexity analysis Implementation results

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Analysis of the Monotonic Lagrangian Grid as an Air Traffic Simulation Tool

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2013年第1期36卷 196-206页

作者： Kaplan, Carolyn Dahm, Johann Oran, Elaine Alexandrov, Natalia Boris, Jay USN Res Lab Labs Computat Phys & Fluid Dynam Lab Prop Energet & Dynam Syst Washington DC 20375 USA Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA USN Res Lab LCP & FD Washington DC 20375 USA NASA Langley Res Ctr NextGen Syst Anal Integrat & Evaluat Project Hampton VA 23681 USA

A new research platform, the Air Traffic Monotonic Lagrangian Grid, has been developed to serve as a simulation tool for easy and fast testing of various air traffic system concepts. The underlying algorithm is the Monotonic Lagrangian Grid, which is a fast nearest-neighbors interaction algorithm used for sorting and tracking many moving and interacting objects. The nodes of the Monotonic Lagrangian Grid represent the locations of individual aircraft, and the grid moves at each time step as the aircraft move. The model is used to simulate a 24 h period of air traffic flow in the National Airspace System, during which there are 41,594 flights, and this requires only 79 s of wall-clock time on a single processor of a 1.3 GHz Altix. An analysis is presented of the number of nearest-neighbor nodes that must be checked to ensure adequate separation among aircraft. An investigation of the effect of removing waypoints from aircraft trajectories indicates that this may result in a significant reduction in total flight time. Finally, the model is compared with the traditional Latitude - Longitude grid approach, in which the airspace volume is partitioned into fixed stationary grid cells. Results of the comparison indicate that the main advantage of the Monotonic Lagrangian Grid method is that it is a general sorting algorithm that can sort on multiple properties, providing more computational efficiency.

关键词： Enhanced Traffic Management System National Airspace System Airspace sorting algorithms Federal Aviation Administration Conflict Detection and Resolution Computer Memory Direct Simulation Monte Carlo Air Transportation System Cruise Altitude

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Novel beetle algorithm for Cartesian grid generation in two dimensions

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JOURNAL OF AIRCRAFT 2000年第5期37卷 927-929页

作者： Srivastava, A Ravichandran, KS Natl Aerosp Labs Computat & Theoret Fluid Dynam Div Bangalore 560017 Karnataka India

A Cartesian grid generator has been coded to obtain a Cartesian grid around an arbitrary geometry in 2D. The grid generation is accomplished by a novel technique employing a Beetle algorithm. The significant parameters in defining the movement of the Beetle and its capture of intersection points are ascertained and implemented within the code. The sample grid generated around several shapes demonstrates the code's versatility. (CSA)

关键词： MDO Optimization Algorithm High Performance Computing Annealing Process Stochastic Optimization Sensitivity Analysis Aircraft Wing Design Parallel Computing sorting algorithms Genetic Algorithm

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Quadripartite Sort

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JOURNAL OF algorithms 1998年第2期28卷 258-271页

作者： Chen, JC Shanghai Jiao Tong Univ Dept Comp Sci Shanghai 200030 Peoples R China

This paper presents an efficient and practical sorting algorithm, called Quadripartite Sort. It lies between MergeSort and QuickSort. This algorithm sorts n elements using bounded workspace and n log n + 1.75n comparisons in the worst case. By empirical testing, we conjecture that this algorithm needs approximately n log n - n comparisons on average. When using m-way merging strategy, where m is a Larger constant, this algorithm becomes an in-place sorting algorithm whose comparison plus exchange total is absolutely minimum among known constant workspace algorithms. For example, using a 256-way merging, the comparison plus exchange total required is approximately 1.2495n log n + O(n) in the worst case. (C) 1998 Academic Press.

关键词： sorting algorithms mergesort quicksort constant workspace

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ENGINEERING A SORT FUNCTION

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SOFTWARE-PRACTICE & EXPERIENCE 1993年第11期23卷 1249-1265页

作者： BENTLEY, JL MCILROY, MD AT & T Bell Laboratories 600 Mountain Avenue Murray Hill NJ 07974 U.S.A.

We recount the history of a new qsort function for a C library. Our function is clearer, faster and more robust than existing sorts. It chooses partitioning elements by a new sampling scheme;it partitions by a novel solution to Dijkstra's Dutch National Flag problem;and it swaps efficiently. Its behavior was assessed with timing and debugging testbeds, and with a program to certify performance. The design techniques apply in domains beyond sorting.

关键词： QUICKSORT sorting algorithms PERFORMANCE TUNING ALGORITHM DESIGN AND IMPLEMENTATION TESTING

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Enhanced Collocation Method for Dynamical Systems Subject to Finite Set Control

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2010年第3期33卷 957-968页

作者： Stanton, Stuart A. Marchand, Belinda G. Univ Texas Austin Dept Aerosp Engn & Engn Mech Austin TX 78712 USA

An enhanced optimization method, rooted in direct collocation, is formulated to treat a specific class of continuous-time hybrid control systems;specifically, dynamical systems that depend on continuous state variables and spatially discrete control variables. In this study, a spatially discrete control variable refers to one that is defined over the continuous-time domain yet is constrained to a range of discrete finite values. This subset of hybrid control systems is termed here as finite set control. Traditionally, optimal control for hybrid systems of this class is formulated in the context of mixed-integer nonlinear programming. The numerical efficiency of these methods, however, is adversely affected by the number of independent control variables and the range of the combined set. The methodology presented in this study focuses on this class of problems: multiple independent control variables, each with a unique range and a switching schedule independent from the others. The resulting formulation leads to a more computationally efficient nonlinear program suitable for the identification of optimal control solutions for this class of hybrid systems.

关键词： Collocation Method Nonlinear Programming Bang Bang Control Discrete Control Control Systems Lunar Lander Aerospace Engineering sorting algorithms Gradient Method Soft Landing

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Engineering Quicksort

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COMPUTER LANGUAGES 1996年第1期22卷 39-47页

作者： Sarwar, SM Sarwar, SA Jaragh, MHA Brandeburg, J NEW YORK INST TECHNOL ACAD COMP LABSOLD WESTBURYNY 11568 KUWAIT UNIV FAC ENGN & PETRDEPT ELECT & COMP ENGNSAFAT 13060KUWAIT

This paper describes the results of a large empirical study to measure the run-time behavior of Quicksort by using various methods of computing the pivot element for medium to large size randomly generated integer data. The results of our study contradict the common notion that Quicksort gives best performance if median of three scheme is used to compute the pivot element and array partitions having <10 elements are sorted by using insertion sort. It was found that Quicksort performs best when median of three scheme is used to decide the pivot element and arrays with <4 elements are hand sorted. Our method gives an average speedup of >9% when compared to the method with a cutoff of 10 and sub-arrays with <10 elements insertion sorted for 1000 less than or equal to N less than or equal to 1.5 x 10(6). Our study shows that advanced hardware features allow for implementation of very fast codes for sorting small arrays, and using such codes instead of insertion sort can lead to substantial improvements for Quicksort, as conjectured by Sedgewick many years ago. Copyright (C) 1996 Elsevier Science Ltd

关键词： experimental algorithms sorting algorithms Quicksort

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