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10th Brazilian Symposium on Geoinformatics, GEOINFO 2008

作者： Volz, Steffen Nicklas, Daniela Grossmann, Matthias Wieland, Matthias Carl von Ossietzky Universität Oldenburg Department of Computing Science Escherweg 2 26121 Oldenburg Germany Universität Stuttgart Department of Applications of Parallel and Distributed Systems Universitätsstr. 38 70569 Stuttgart Germany Universität Stuttgart Institute of Architecture of Application Systems Universitätsstr. 38 70569 Stuttgart Germany

The world of spatial data is split into individual data source islands that have different thematic or spatial focuses. When attempting to integrate those data sources, severe challenges arise, since for most GIS application domains a spatial integration schema does not exist. This is also true for the newly emerging domain of mobile, context-aware applications. Since the users of these systems are mobile, transborder access to spatial data or context models is crucial for global deployment. The basis for this work is the Nexus Augmented World Schema, a conceptual schema that serves as an integration standard for autonomous spatial context servers. This paper analyzes some major spatial data standards, especially with respect to the requirements of a spatial integration schema for context-aware applications and illustrates the Nexus approach.

关键词： Integration

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Biomedical image processing with GPGPU using CUDA

Biomedical image processing with GPGPU using CUDA

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Proceedings of the International Convention MIPRO

作者： A. R. Firstauthor I. B. Secondauthor G. V. Thirdauthor P. B. Fourthauthor M. K. Fifthauthor Óbuda University/John von Neumann Faculty of Informatics Budapest Hungary Semmelweiss University/Znd Department of Internal Medicine Budapest Hungary MTA SZTAKI/Laboratory of Parallel and Distributed Computing Budapest Hungary

The main aim of this work is to show, how the GPGPUs can be used to speed up certain image processing methods. The algorithm explained in this paper is used to detect nuclei on (HE - hematoxilin eosin) stained colon tissue sample images, and includes a Gauss blurring, an RGB-HSV color space conversion, a fixed binarization, an ultimate erode procedure and a local maximum search. Since the images retrieved from the digital slides require significant storage space (up to few hundred megapixels), the usage of GPGPUs to speed up image processing operations is necessary in the interest of achieving reasonable processing time. The CUDA software development kit was used to develop algorithms to GPUs made by NVIDIA. This work focuses on how to achieve coalesced global memory access when working with three-channel RGB images, and how to use the on-die shared memory efficiently. The exact test algorithm also included a linear connected component labeling, which was running on the CPU, and with iterative optimization of the GPU code, we managed to achieve significant speed up in well defined test environment.

关键词： Graphics processing unit Instruction sets Image processing Kernel Optimization Memory management Pixel

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Replication-Based Fault-Tolerance for Large-Scale Graph Processing

Replication-Based Fault-Tolerance for Large-Scale Graph Proc...

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International Conference on Dependable Systems and Networks (DSN)

作者： Peng Wang Kaiyuan Zhang Rong Chen Haibo Chen Haibing Guan Shanghai Key Laboratory of Scalable Computing and Systems Institute of Parallel and Distributed Systems Shanghai Jiao Tong University Department of Computer Science Shanghai Jiao Tong University

The increasing algorithm complexity and dataset sizes necessitate the use of networked machines for many graph-parallel algorithms, which also makes fault tolerance a must due to the increasing scale of machines. Unfortunately, existing large-scale graph-parallel systems usually adopt a distributed checkpoint mechanism for fault tolerance, which incurs not only notable performance overhead but also lengthy recovery time. This paper observes that the vertex replicas created for distributed graph computation can be naturally extended for fast in-memory recovery of graph states. This paper proposes Imitator, a new fault tolerance mechanism, that supports cheaply maintenance of vertex states by replicating vertex states to their replicas during normal message exchanges, and provides fast in-memory reconstruction of failed vertices from replicas in other machines. Imitator has been implemented by extending Hama, a popular open-source clone of Pregel. Evaluation shows that Imitator incurs negligible performance overhead (less than 5% for all cases) and can recover from failures of more than one million of vertices with less than 3.4 seconds.

关键词： Fault tolerance Fault tolerant systems Computer crashes Checkpointing Synchronization Clustering algorithms Computational modeling

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Grid-based metadata services

Grid-based metadata services

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International Working Conference on Scientific and Statistical Database Management

作者： E. Deelman G. Singh M.P. Atkinson A. Chervenak N.P. Chue Hong C. Kesselman S. Patil L. Pearlman Mei-Hui Su Information Sciences Institute University of Southern California USA Department of Computing Science Division of Informatics University of Glasgow University of Edinburgh UK Edinburgh Parallel Computing Centre UK

Data sets being managed in grid environments today are growing at a rapid rate, expected to reach 100s of petabytes in the near future. Managing such large data sets poses challenges for efficient data access, data publication and data discovery. In this paper we focus on the data publication and discovery process through the use of descriptive metadata. This metadata describe the properties of individual data items and collections. We discuss issues of metadata services in service rich environments, such as the grid. We describe the requirements and the architecture for such services in the context of grid and the available grid services. We present a data model that can capture the complexity of the data publication and discovery process. Based on that model we identify a set of interfaces and operations that need to be provided to support metadata management. We present a particular implementation of a grid metadata service, basing it on existing grid services technologies. Finally we examine alternative implementations of that service.

关键词： Collaboration Environmental management Physics Astronomy Instruments Data analysis Image databases Context-aware services Data models Space technology

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SPECTRE: Supporting consumption policies in window-based parallel complex event processing

arXiv

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arXiv 2017年

作者： Mayer, Ruben Slo, Ahmad Tariq, Muhammad Adnan Rothermel, Kurt Gräber, Manuel Ramachandran, Umakishore Institute of Parallel and Distributed Systems University of Stuttgart Department of Computer Science Fast - National University of Computer and Emerging Sciences Islamabad Pakistan College of Computing Georgia Institute of Technology United States

distributed Complex Event Processing (DCEP) is a paradigm to infer the occurrence of complex situations in the surrounding world from basic events like sensor readings. In doing so, DCEP operators detect event patterns on their incoming event streams. To yield high operator throughput, data parallelization frameworks divide the incoming event streams of an operator into overlapping windows that are processed in parallel by a number of operator instances. In doing so, the basic assumption is that the different windows can be processed independently from each other. However, consumption policies enforce that events can only be part of one pattern instance;then, they are consumed, i.e., removed from further pattern detection. That implies that the constituent events of a pattern instance detected in one window are excluded from all other windows as well, which breaks the data parallelism between different windows. In this paper, we tackle this problem by means of speculation: Based on the likelihood of an event's consumption in a window, subsequent windows may speculatively suppress that event. We propose the SPECTRE framework for speculative processing of multiple dependent windows in parallel. Our evaluations show an up to linear scalability of SPECTRE with the number of CPU cores. Copyright © 2017, The Authors. All rights reserved.

关键词： Data handling

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An efficient local address generation for the block-cyclic distribution

An efficient local address generation for the block-cyclic d...

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IEEE International Conference on Algorithms and Architectures for parallel Processing (ICAP)

作者： Oh-Young Kwon Tae-Geun Kim Tack-Don Han Sung-Bong Yang Shin-Dug Kim Distributed Computing Laboratory Systems Engineering Research Institute Taejon South Korea Parallel Processing System Laboratory Department of Computer Science Yonsei University Seoul South Korea

ISBN: (纸本)0780342291

In order to generate local addresses for an array section A(l:h:s) with block-cyclic distribution, an efficient compiling method is required. In this paper, two local address generation methods for the block-cyclic distribution are presented. One is a simple local address generation method that is modified from the virtual-block scheme. The other is a linear-time /spl Delta/M table construction method. The array elements of A(l:h:s) to be accessed at run-time build up a family of lines. By using the equation of the lines, a /spl Delta/M table can be generated in O(k) time. Experimental results show that a simple local address generation method has poor performance but a linear-time /spl Delta/M table generation method is faster than other algorithms in /spl Delta/M table generation time and access time for 10,000 array elements.

关键词： Runtime Equations distributed computing Systems engineering and theory parallel processing Laboratories Computer science parallel languages Upper bound Automata

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parallel biomedical image processing with GPGPUs in cancer research

Parallel biomedical image processing with GPGPUs in cancer r...

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International Symposium on Logistics and Industrial informatics, LINDI

作者： Attila Reményi Sándor Szénási István Bándi Zoltán Vámossy Gábor Valcz Pál Bogdanov Szabolcs Sergyán Miklos Kozlovszky John von Neumann Faculty of Informatics Óbuda University Budapest Hungary 2nd Department of Internal Medicine Semmelweiss University Budapest Hungary Laboratory of Parallel and Distributed Computing MTA SZTAKI Budapest Hungary

The main aim of this work is to show, how GPGPUs can facilitate certain type of image processing methods. The software used in this paper is used to detect special tissue part, the nuclei on (HE - hematoxilin eosin) stained colon tissue sample images. Since pathologists are working with large number of high resolution images - thus require significant storage space -, one feasible way to achieve reasonable processing time is the usage of GPGPUs. The CUDA software development kit was used to develop processing algorithms to NVIDIA type GPUs. Our work focuses on how to achieve better performance with coalesced global memory access when working with three-channel RGB tissue images, and how to use the on-die shared memory efficiently.

关键词： Graphics processing unit Instruction sets Image processing Memory management Optimization Kernel Colon

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Automated Controller Placement for Software-Defined Networks to Resist DDoS Attacks

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Computers, Materials & Continua 2021年第9期68卷 3147-3165页

作者： Muhammad Reazul Haque Saw Chin Tan Zulfadzli Yusoff Kashif Nisar Lee Ching Kwang Rizaludin Kaspin Bhawani Shankar Chowdhry Rajkumar Buyya Satya Prasad Majumder Manoj Gupta Shuaib Memon Faculty of Computing&Informatics Multimedia UniversityPersiaran MultimediaCyberjaya63100SelangorMalaysia Faculty of Engineering Multimedia UniversityPersiaran MultimediaCyberjaya63100SelangorMalaysia Faculty of Computing and Informatics University Malaysia SabahJalan UMSKota Kinabalu Sabah88400Malaysia Telekom Malaysia Research&Development TM Innovation CentreCyberjaya63000SelangorMalaysia National Center of Robotics and Automation Mehran University of Engineering&TechnologyJamshoroPakistan Department of Computer Science and Engineering Hanyang UniversitySeoul04763South Korea School of Electrical and Electronic Engineering Nanyang Technological University639798Singapore Cloud Computing and Distributed Systems Laboratory The University of MelbourneMelbourneVIC 3053Australia Department of Electrical and Electronic Engineering Bangladesh University of Engineering and Technology(BUET)Dhaka1205Bangladesh Department of Electronics and Communication Engineering JECRC UniversityVidhaniJaipur303905India Auckland Institute of Studies Mt AlbertAucklandNew Zealand

In software-defined networks(SDNs),controller placement is a critical factor in the design and planning for the future Internet of Things(IoT),telecommunication,and satellite communication *** research has concentrated largely on factors such as reliability,latency,controller capacity,propagation delay,and energy ***,SDNs are vulnerable to distributed denial of service(DDoS)attacks that interfere with legitimate use of the *** ever-increasing frequency of DDoS attacks has made it necessary to consider them in network design,especially in critical applications such as military,health care,and financial services networks requiring high *** propose a mathematical model for planning the deployment of SDN smart backup controllers(SBCs)to preserve service in the presence of DDoS *** a number of input parameters,our model has two distinct ***,it determines the optimal number of primary controllers to place at specific locations or nodes under normal operating ***,it recommends an optimal number of smart backup controllers for use with different levels of DDoS *** goal of the model is to improve resistance to DDoS attacks while optimizing the overall cost based on the *** simulated results demonstrate that the model is useful in planning for SDN reliability in the presence of DDoS attacks while managing the overall cost.

关键词： SDN automated controller placement SBC ILP DDoS attack

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The Interplay Between Timeliness and Scalability in Cloud Monitoring Systems

The Interplay Between Timeliness and Scalability in Cloud Mo...

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IEEE Symposium on Computers and Communication

作者： Guilherme da Cunha Rodrigues Rodrigo N. Calheiros Marcio Barbosa de Carvalho Carlos Raniery Paula dos Santos Lisandro Zambenedetti Granville Liane Tarouco Rajkumar Buyya Computer Networks Group Institute of Informatics Federal University of Rio Grande do Sul Cloud Computing and Distributed Systems (CLOUDS) Laboratory Department of Computing and Information Systems The University of Melbourne Department of Applied Computing Federal University of Santa Maria

ISBN: (纸本)9781467371957

Cloud computing is a groundbreaking solution to acquire computational resources on demand. To deliver high quality cloud services and provide features such as reduced costs and availability to customers, a cloud, like any other computational system, needs to be properly managed in accordance with its characteristics (e.g., scalability, elasticity, timeliness). In this scenario, cloud monitoring is a key to achieve it. To properly work, cloud monitoring systems need to meet several requirements such as scalability, accuracy, and timeliness. This paper aims to unveil the trade-off between timeliness and scalability. Evaluations demonstrate the mutual influence between scalability and timeliness based on monitoring parameters (e.g., monitoring topologies, frequency sampling). Results show that non-deep monitoring topologies and decreasing the frequency sampling assist to reduce the mutual influence between timeliness and scalability.

关键词： Scalability CLOUDS Clouds monitoring systems Monitoring parameters Cloud computing

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Anti-Jamming Schedules for Wireless Data Broadcast Systems

Anti-Jamming Schedules for Wireless Data Broadcast Systems

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IEEE International Symposium on Information Theory

作者： Paolo Codenotti Alexander Sprintson Jehoshua Bruck Department of Computer Science University of Chicago Chicago IL USA Department of Electrical and Computer Engineering Texas A and M University TX USA Parallel and Distributed Computing Group California Institute of Technology Pasadena CA USA

ISBN: (纸本)142440505X

Modern society is heavily dependent on wireless networks for providing voice and data communications. Wireless data broadcast has recently emerged as an attractive way to disseminate dynamic data to a large number of clients. In data broadcast systems, the server proactively transmits the information on a downlink channel; the clients access the data by listening to the channel. Wireless data broadcast systems can serve a large number of heterogeneous clients, minimizing power consumption as well as protecting the privacy of the clients' locations. The availability and relatively low cost of antennas resulted in a number of potential threats to the integrity of the wireless infrastructure. In particular, the data broadcast systems are vulnerable to jamming, i.e., the use of active signals to prevent data broadcast. The goal of jammers is to cause disruption, resulting in long waiting times and excessive power consumption. In this paper we investigate efficient schedules for wireless data broadcast that perform well in the presence of a jammer. We show that the waiting time of client can be reduced by adding redundancy to the schedule and establish upper and lower bounds on the achievable minimum waiting time under different requirements on the staleness of the transmitted data

关键词： Broadcasting Jamming Energy consumption Wireless networks Data communication Wireless communication Network servers Downlink Power system protection Data privacy

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