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Parallel and scalable Dunn Index for the validation of big data clusters

PARALLEL COMPUTING 2021年 102卷 102751-102751页

作者： Ben Ncir, Chiheb-Eddine Hamza, Abdallah Bouaguel, Waad Univ Jeddah Coll Business Jeddah Saudi Arabia Univ Tunis LARODEC Lab ISG Tunis Tunisia

Parallelizing data clustering algorithms has attracted the interest of many researchers over the past few years. Many efficient parallel algorithms were proposed to build partitioning over a huge volume of data. the effectiveness of these algorithms is attributed to the distribution of data among a cluster of nodes and to the parallel computation models. Although the effectiveness of parallel models to deal with increasing volume of data little work is done on the validation of big clusters. To deal with this issue, we propose a parallel and scalable model, referred to as S-DI (Scalable Dunn Index), to compute the Dunn Index measure for an internal validation of clustering results. Rather than computing the Dunn Index on a single machine in the clustering validation process, the new proposed measure is computed by distributing the partitioning among a cluster of nodes using a customized parallel model under Apache Spark framework. the proposed S-DI is also enhanced by a Sketch and Validate sampling technique which aims to approximate the Dunn Index value by using a small representative data-sample. Different experiments on simulated and real datasets showed a good scalability of our proposed measure and a reliable validation compared to other existing measures when handling large scale data.

关键词： Distributed and parallel computing Spark framework Sampling Big data analysis Clustering validity Dunn Index

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Efficient Processing of Narrow Range Queries in Multi-dimensional data structures

Efficient Processing of Narrow Range Queries in Multi-dimens...

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international Symposium on database Engineering and Applications (IDEAS)

作者： Michal Kratky Vaclav Snasel Jaroslav Pokorny Pavel Zezula VSB-Technical University of Ostrava Czech Republic Charles University Prague Czech Republic Masaryk University Brno Czech Republic

Multi-dimensional data structures are applied in many real index applications, i.e. data mining, indexing multimedia data, indexing of text documents and so on. Many index structures and algorithms have been proposed. there are two major approaches to multi-dimensional indexing: data structures to indexing metric and vector spaces. R-trees, R*-trees and (B)UB-trees are representatives of the vector data structures. these data structures provide efficient processing of many types of queries, i.e. point queries, range queries and so on. As far as the vector data structures are concerned, the range query retrieves all points in defined hyper box in an n-dimensional space. the narrow range query is an important type of the range query. Its processing is inefficient in vector data structures. Moreover, the efficiency decreases as the dimension of the indexed space increases. We depict an application of the signature for more efficient processing of narrow range queries. the approach puts the signature into the multi-dimensional data structures like R-tree or UB-tree but original functionalities are preserved, i.e. the range query algorithm for general range query. the novel data structure is called the signature data structure, e.g., signature R-tree or signature UB-tree

关键词： data structures Indexing Multimedia databases Extraterrestrial measurements Information retrieval data mining Relational databases Content based retrieval Biomedical imaging Geography

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On-board processing of video image sequences

On-board processing of video image sequences

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international workshop on Signal Processing for Space Communications (SPSC)

作者： J. Dahl Andersen O. Chanrion S. Forchhammer I. Lundgaard Rasmussen Department of Photonics Engineering Technical University of Denmark Denmark National Space Institute Technical University of Denmark Denmark

the ldquoatmosphere-space interactions monitorrdquo (ASIM) is a payload to be mounted on one of the external platforms of the Columbus module of the international Space Station (ISS). the instruments include six video cameras, six photometers and one X-ray detector. the main scientific objective of the mission is to study transient luminous events (TLE) above severe thunderstorms: the sprites, jets and elves. Other atmospheric phenomena are also studied including aurora, gravity waves and meteors. As part of the ASIM Phase B study, on-board processing of data from the cameras is being developed and evaluated. On-board there are six video cameras each capturing images of 1024times1024 pixels of 12 bpp at a frame rate of 15 fps, thus totalling 1080 Mbits/s. In comparison the average downlink data rate for these images is projected to be 50 kbit/s. this calls for efficient on-board processing to select and compress the data. algorithms for on-board processing of the image data are presented as well as evaluation of the performance. the main processing steps are event detection, image cropping and image compression. the on-board processing requirements are also evaluated.

关键词： Image sequences Cameras Image coding Monitoring Payloads international Space Station Instruments Photometry X-ray detectors Sprites (computer)

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One-pass encoding of connected components in multivalued images

One-pass encoding of connected components in multivalued ima...

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international Conference on Pattern Recognition

作者： E. Mandler M.F. Oberlander Daimler-Benz Research Ulm Germany

A method of representing connected components in multivalued images is proposed, and an efficient, sequential, one-pass algorithm for generating the border-line chain code for each component is introduced. Simultaneously, the algorithm produces for each component a list of all neighboring components that are encountered during a walk around the border line, thus providing full topological information. the number of different pixel values does not affect performance.< >

关键词： Image coding Pixel Image processing data structures Image storage Image segmentation Classification algorithms Shape Navigation Image representation

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Computer guided product EMC compliance on user's workshop by means of cloud computing - methodologies and algorithms

Computer guided product EMC compliance on user's workshop by...

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international Conference on Industrial and Information Systems, ICIIS

作者： Wei Wu Yuejia Wu Institute of Innovation WEIWU INFO Lisbon Portugal Dept. of Cloud Computing Technology Zhoushan Puhua Elec. Info. Tech LTD Zhoushan China

All products are obligated to pass Electromagnetic Compatibility (EMC) tests before sale. Due to the uncertainty of Electromagnetic Interference (EMI) location in product, the product EMC compliance is expensive and time consuming. In this paper we present a novel solution to assist industrial users in product EMC compliance, which is a public Computer Aided EMC compliance service platform in Cloud, accessible through Internet by Desktop, Laptop, Pad or Smart Phone. the industrial users may measure voltage signals on EUT with a general-purpose oscilloscope, and upload the data to platform where the data are analyzed and the analysis results indicate the EMI location and EMI level on EUT, to guide users efficiently and effectively modify EUT to approach EMC compliance. It is low cost and easy to use, users only pay the Computing time in Cloud, no software installation, no operation skill and no EMC expertise are required. Methodologies and algorithms of proposed solution are introduced, and illustrated by example.

关键词： Conferences Computers Electromagnetic compatibility Electromagnetic interference Oscilloscopes Europe

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Robust satellite image analysis using probabilistic learning based graph optimization

Robust satellite image analysis using probabilistic learning...

引用

international workshop on Image Analysis for Multimedia Interactive Services, WIAMIS

作者： Yangyu Tao Lin Liang Yingqing Xu MOE-Microsoft Key Laboratory USTC Hefei China Microsoft Research Asia Beijing China

We study the satellite image analysis problem with focus on extracting the man-made buildings. Instead of assuming simple rectangular building shape as in the most of previous work, we apply probabilistic learning method to statistical modeling the building structures. the model can achieve high robustness to large shape variation. We also propose a novel energy function to incorporate the statistical model into a graph optimization framework. Once the graph is constructed on image edges, the buildings can be extracted as closed cycles on graph efficiently and accurately. Experiments on real images demonstrate the effectiveness and robustness of the approach.

关键词： Robustness Satellites Image analysis Buildings Shape data mining Image edge detection Asia Laboratories Learning systems

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A map matching algorithm for intersections based on Floating Car data

A map matching algorithm for intersections based on Floating...

引用

international Conference on Advanced Communication Technology (ICACT)

作者： Wenjie Liao Weifeng Lv Tongyu Zhu DongDong Wu State Key Laboratory of Software Development Environment Beihang University China

the traditional map matching algorithms consider little about the complicated structure of the road network, and regard all roads as the same. However, in the transportation information system using the floating car data (FCD), the GPS sampling rate is low, and it is probable to figure out the incorrect result when the vehicle is in the intersection area. To solve this problem, this paper proposes a bidirectional heuristic map matching algorithm for intersections based on a data structure for intersections. this algorithm apply the data structure of intersections to separates the intersection part from common map matching, decreases the FCD map matching mistakes that caused by the complicated road network and the GPS errors, and increases the accuracy of map matching.

关键词： Sampling methods Global Positioning System Road vehicles Network topology Road transportation data structures Traffic control Information systems Intelligent transportation systems Navigation

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Visionaray: A Cross-Platform Ray Tracing Template Library

Visionaray: A Cross-Platform Ray Tracing Template Library

引用

workshop on Software Engineering and Architectures for Realtime Interactive Systems (SEARIS)

作者： Stefan Zellmann Daniel Wickeroth Ulrich Lang University of Cologne

ISBN: (数字)9781538662748

ISBN: (纸本)9781538662755

We present the software architecture of the C++ ray tracing template library Visionaray, which provides generic algorithms and data structures as building blocks for applications that traverse rays through 3-D space. While many state of the art ray tracing libraries are vendor specific and focus only on acceleration data structure traversal, Visionaray is cross platform compatible and implements several ray tracing-related tasks such as parallel ray generation, shading, Monte Carlo integration, or texture sampling. Visionaray was developed with a strong focus on real-time and interactive rendering on high performance computing platforms. the generic programming approach allows for loose coupling of algorithms and efficient binary code that is optimized for data and instruction cache utilization. We discuss implementation details and software architecture considerations to achieve real-time performance on hardware platforms ranging from single-board mini computers to GPGPUs. We prove the effectiveness of our approach by evaluating and discussing four case studies that focus on real-time rendering, scientific visualization, and virtual reality.

关键词： Libraries Ray tracing C++ languages data structures Real-time systems Rendering (computer graphics) Programming

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On the formation of periodic electric field domains in p-Si/SiGe quantum cascade structures

On the formation of periodic electric field domains in p-Si/...

引用

international workshop on Computational Electronics

作者： Ikonic Harrison Kelsall School of Electronic and Electrical Engineering University of Leeds Leeds UK

Biased semiconductor quantum well cascade structures, as are nowadays used in intersubband infrared photodetectors and lasers, are well known to be susceptible to the formation of electric field domains. the homogeneous electric field in a structure is broken, due to charge redistribution over individual wells and the appearance of the associated space-charge contribution to the potential. In this work we consider the formation of stationary periodic domains in p-type Si/SiGe cascade structures. Hole transport is described via scattering between quantized subbands in subsequent wells, as calculated using the 6/spl times/6 k.p method which accounts for the full anisotropy of heavy hole and light hole subbands. the scattering mechanisms taken into account are deformation potential (acoustic and optical phonons), alloy disorder, and carrier-carrier scattering. In order to find the possibility of domain formation the hole scattering rates between all pairs of states in subsequent wells in a homogeneous cascade are calculated, as a function of the electric field, taking the carrier heating (thermal self-consistency) into account. these are then used (via interpolation) to solve a system of rate equations for the subband populations in each quantum well, coupled with the discretized Poisson equation. In order to avoid use of contact boundary conditions, for which no experimental data is presently available, we use periodic boundary conditions, in which the electric field distribution in a long homogeneous cascade is assumed to break into an arbitrary number of periodic segments. this is a generalization of the period-doubling model described in (Ryzhii et al. (2000).

关键词： Quantum wells Charge carrier mobility Electric fields Germanium alloys Silicon alloys Infrared detectors Photodetectors

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dIP: A Non-intrusive Debugging IP for Dynamic data Race Detection in Many-Core

dIP: A Non-intrusive Debugging IP for Dynamic Data Race Dete...

引用

international Symposium on Parallel Architectures, algorithms and Networks (ISPAN)

作者： Chi-Neng Wen Shu-Hsuan Chou Tien-Fu Chen National Chung Cheng University Chiayi Taiwan

Traditional debug facilities are limited in providing debugging requirements for multicore parallel programming. Synchronization problems or bugs due to race conditions are particularly difficult to detect with software debugging tools. this work presents a fast and feasible hardware-assistant solution for many-core non-intrusive debugging. the key idea is to keep tracks of data accesses of shared memory areas and their lock synchronization activities by proposed data structures in proposed debugging IP (dIP). A page-based shared variable cache is provided to keep shared variables as long as possible, and an inexpensive pluggable off-chip RAM can eliminate the false-positive rate efficiently. To decrease the debugging traffic block, this work provides a thread library to specify shared memory/lock events and transmit those events to the dIP by a small proper hardware co-processor (eXtend dIP) of each core. Our experimental result shows the debugging traffic block (worse-case) by increasing cores, and adding tolerance buffers in XdIP can efficiently ease off. Moreover, the real workloads (SPLASH-2, MPEG-4, and H.264) are executed by the dIP non-instructive race-detection with only 4.7%~12.2% slow down in average. Finally, the hardware cost of dIP is also low when the growing of many-core.

关键词： Random access memory Hardware Multicore processing Parallel programming Computer bugs Software debugging data structures Read-write memory Yarn Libraries

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