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Topology awareness algorithm for virtual network mapping

Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第3期13卷 178-186页

作者： Xiao-ling LI Huai-min WANG Chang-guo GUO Bo DING Xiao-yong LI Wen-qi BI Shuang TAN National Key Laboratory of Parallel and Distributed Processing National University of Defense Technology.Changsha 410073China School of Computer National University of Defense TechnologyChangsha 410073China China Electronic Systems Engineering Corporation Beijing 100039China The Northern Institute of Electronic Equipment of China Beijing 100083China

Network virtualization is recognized as an effective way to overcome the ossification of the Internet. However, the virtual network mapping problem (VNMP) is a critical challenge, focusing on how to map the virtual networks to the substrate network with efficient utilization of infrastructure resources. The problem can be divided into two phases: node mapping phase and link mapping phase. In the node mapping phase, the existing algorithms usually map those virtual nodes with a complete greedy strategy, without considering the topology among these virtual nodes, resulting in too long substrate paths (with multiple hops). Addressing this problem, we propose a topology awareness mapping algorithm, which considers the topology among these virtual nodes. In the link mapping phase, the new algorithm adopts the k-shortest path algorithm. Simulation results show that the new algorithm greatly increases the long-term average revenue, the acceptance ratio, and the long-term revenue-to-cost ratio (R/C).

关键词： Network virtualization Ossification Virtual network (VN) mapping Substrate network (SN) Topology awareness Acceptance ratio

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Implicit-Explicit Error Indicator based on Approximation Order

Implicit-Explicit Error Indicator based on Approximation Ord...

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International Multidisciplinary Conference on Computer and Energy Science (SpliTech)

作者： Mitja Janč ič Filip Strniš a Gregor Kosec Parallel and Distributed Systems Laboratory Joief Stefan Institute Joief Stefan International Postgraduate School Ljubljana Slovenia Parallel and Distributed Systems Laboratory Joief Stefan Institute Ljubljana Slovenia

ISBN: (纸本)9781665488280

With the immense computing power at our disposal, the numerical solution of partial differential equations (PDEs) is becoming a day-to-day task for modern computational scientists. However, the complexity of real-life problems is such that tractable solutions do not exist. This makes it difficult to validate the numerically obtained solution, so good error estimation is crucial in such cases. It allows the user to identify problematic areas in the computational domain that may affect the stability and accuracy of the numerical method. Such areas can then be remedied by either h- or p-adaptive procedures. In this paper, we propose to estimate the error of the numerical solution by solving the same governing problem implicitly and explicitly, using a different approximation order in each case. We demonstrate the newly proposed error indicator on the solution of a synthetic two-dimensional Poisson problem with tractable solution for easier validation. We show that the proposed error indicator has good potential for locating areas of high error.

关键词： Poisson equations Error analysis Complexity theory Task analysis Numerical stability

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Hyperviscosity stabilisation of the RBF-FD solution to natural convection 9

Hyperviscosity stabilisation of the RBF-FD solution to natur...

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9th European Thermal Sciences Conference, EUROTHERM 2024

作者： Vaupotič, Ziga Rot, Miha Kosec, Gregor Parallel and Distributed Systems Laboratory Jozef Stefan Institute Jamova Cesta 39 Ljubljana1000 Slovenia Jozef Stefan International Postgraduate School Jamova Cesta 39 Ljubljana1000 Slovenia

The numerical stability of fluid flow is an important topic in computational fluid dynamics as fluid flow simulations usually become numerically unstable in the turbulent regime. Many mesh-based methods have already established numerical dissipation procedures that dampen the effects of the unstable advection term. When it comes to meshless methods, the prominent stabilisation scheme is hyperviscosity. It introduces numerical dissipation in the form of a higher-order Laplacian operator. Many papers have already discussed the general effects of hyperviscosity and its parameters. However, hyperviscosity in flow problems has not yet been analyzed in depth. In this paper, we discuss the effects of hyperviscosity on natural convection flow problems as we approach the turbulent regime. © Published under licence by IOP Publishing Ltd.

关键词： Stabilization

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Glinda: A framework for accelerating imbalanced applications on heterogeneous platforms 13

Glinda: A framework for accelerating imbalanced applications...

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2013 ACM International Conference on Computing Frontiers, CF 2013

作者： Shen, Jie Varbanescu, Ana Lucia Arntzen, Michael Simons, Dick G. Henk Sips Parallel and Distributed Systems Group Delft University of Technology Netherlands Air Transport and Operations Aerospace Engineering Delft University of Technology Netherlands Dutch National Aerospace Laboratory Netherlands

ISBN: (纸本)9781450320535

Heterogeneous platforms integrating different processors like GPUs and multi-core CPUs become popular in high performance computing. While most applications are currently using the homogeneous parts of these platforms, we argue that there is a large class of applications that can benefit from their heterogeneity: massively parallel imbalanced applications. Such applications emerge, for example, from variable time step based numerical methods and simulations. In this paper, we present Glinda, a framework for accelerating imbalanced applications on heterogeneous computing platforms. Our framework is able to correctly detect the application workload characteristics, make choices based on the available parallel solutions and hardware configuration, and automatically obtain the optimal workload decomposition and distribution. Our experiments on parallelizing a heavily imbalanced acoustic ray tracing application show that Glinda improves application performance in multiple scenarios, achieving up to 12× speedup against manually configured parallel solutions. Copyright 2013 ACM.

关键词： Ray tracing

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Optimal content placement for en-route web caching

Optimal content placement for en-route web caching

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IEEE International Symposium on Network Computing and Applications

作者： A. Jiang J. Bruck Parallel and Distributed Systems Laboratory California Institute of Technology Pasadena CA USA

This paper studies the optimal placement of web files for en-route web caching. It is shown that existing placement policies are all solving restricted partial problems of the file placement problem, and therefore give only sub-optimal solutions. A dynamic programming algorithm of low complexity which computes the optimal solution is presented. It is shown both analytically and experimentally that the file-placement solution output by our algorithm outperforms existing en-route caching policies. The optimal placement of web files can be implemented with a reasonable level of cache coordination and management overhead for en-route caching; and importantly, it can be achieved with or without using data prefetching.

关键词： Routing Network servers File servers Dynamic programming Heuristic algorithms Algorithm design and analysis Web server Prefetching Web sites World Wide Web

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Machine learning methods in Smartphone-Based Activity Recognition

Machine learning methods in Smartphone-Based Activity Recogn...

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International Symposium on Applied Computational Intelligence and Informatics ( SACI)

作者： Istvan Pintye Laboratory of Parallel and Distributed Systems Institute for Computer Science and Control (SZTAKI) Hungary

ISBN: (数字)9781728173771

ISBN: (纸本)9781728173788

In this paper, we present a system for human physical Activity Recognition (AR) using smartphone with embedded sensors. This paper addresses the question whether there is a comfortable way to predict human activities based on collected data from smartphone embedded gyroscope and accelerometer. Computational background of this work based on self-learning machine learning methods. In order to train the machine learning algorithms, The University of California, Irvine (UCI) dataset was used and the different models were compared. After selecting the best model further modifications were suggested in order to improve the accuracy of the model. At the end 96.88% accuracy was reached.

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JCDTA: The Data Trading Archtecture Design in JointCloud Computing 24

JCDTA: The Data Trading Archtecture Design in JointCloud Com...

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24th IEEE International Conference on parallel and distributed systems, ICPADS 2018

作者： Yue, Xikun Wang, Huaimin Liu, Wei Li, Wei Shi, Peichang Ouyang, Xue Science and Technology on Parallel and Distributed Laboratory National University of Defense Technology Changsha China Laboratory of Software Engineering for Complex Systems National University of Defense Technology Changsha China Troops No.75835 PLA China China

ISBN: (纸本)9781538673089

JointCloud computing is a new generation cloud computing model based on collaboration among Cloud Service Providers, making resources from multiple clouds deeply integrated., and supporting customize cloud service. To achieve the data confirmation Right when doing data trading to prevent resell is one of the most important challenges faced by such JointCloud environment. In this paper, we propose the JointCloud Computing Data Trading Architecture (JCDTA), an optimized data trading architecture for cross-stakeholder. Firstly, the announced mechanism is used to extract the data resources summary and the owner information into blockchain. Secondly, the untampering of the blockchain is used to record the data resources information, such as data resources statement information, data resources transaction records and data resources operation records. Finally, the supervision mechanism confirms the declaration of the data sources while the encryption technology ensures the privacy of the data resources. JCDTA guarantees the security and the reliability of data trading in the JointCloud environment and ensures the value invariance of data resources. © 2018 IEEE.

关键词： Blockchain

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Solution of a low Prandtl number natural convection benchmark by a local meshless method

Solution of a low Prandtl number natural convection benchmar...

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作者： Kosec, Gregor Šarler, Božidar Laboratory for Parallel and Distributed Computing Jožef Stefan Institute Ljubljana Slovenia Laboratory for Multiphase Processes University of Nova Gorica Nova Gorica Slovenia Laboratory for Advanced Materials Systems Centre of Excellence for Biosensorics Automation and Process Control Solkan Slovenia

Purpose - The purpose of this paper is to present the solution of a highly nonlinear fluid dynamics in a low Prandtl number regime, typical for metal-like materials, as defined in the call for contributions to a numerical benchmark problem for 2D columnar solidification of binary alloys. The solution of such a numerical situation represents the first step towards understanding the instabilities in a more complex case of macrosegregation. Design/methodology/ approach - The involved temperature, velocity and pressure fields are represented through the local approximation functions which are used to evaluate the partial differential operators. The temporal discretization is performed through explicit time stepping. Findings - The performance of the method is assessed on the natural convection in a closed rectangular cavity filled with a low Prandtl fluid. Two cases are considered, one with steady state and another with oscillatory solution. It is shown that the proposed solution procedure, despite its simplicity, provides stable and convergent results with excellent computational performance. The results show good agreement with the results of the classical finite volume method and spectral finite element method. Originality/value - The solution procedure is formulated completely through local computational operations. Besides local numerical method, the pressure velocity is performed locally also, retaining the correct temporal transient. © Emerald Group Publishing Limited.

关键词： Numerical methods

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A Connectivity-Enhanced Multi-Task Learning based on Anatomical Priors for 3D Class-Balanced Pulmonary Airway Segmentation

A Connectivity-Enhanced Multi-Task Learning based on Anatomi...

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2024 IEEE International Conference on Bioinformatics and Biomedicine, BIBM 2024

作者： Jia, Yan Dou, Yong Qiao, Peng Cheng, Yuqing Xu, Kele He, Zhouyu National University of Defense Technology National Key Laboratory of Parallel and Distributed Computing College of Computer Science and Technology Changsha China National University of Defense Technology College of Systems Engineering Changsha China

ISBN: (纸本)9798350386226

Accurate and efficient airway segmentation is essential for evaluating pulmonary diseases, aiding diagnosis, reducing the preoperative burden of airway identification, and minimizing patient discomfort during prolonged surgeries. However, current pulmonary airway reconstruction techniques are hindered by two major challenges: difficulty in accurately reconstructing fine airway branches due to the tendency to overlook small targets, and insufficient structural connectivity leading to frequent branch discontinuities within the airway tree. These limitations directly affect the clinical applicability of reconstructed airways. To overcome these challenges, a novel 3D pulmonary airway segmentation multi-task framework is proposed, designed to enhance the performance of existing backbone models. This approach integrates Anatomical Prior-Based Multi-Task Learning (AP-MTL) through the use of Gaussian-constructed connectivity-enhanced isosurfaces, significantly improving the network's ability to maintain airway continuity. Additionally, a Class-Balanced CT Density Distribution Reconstruction mechanism (DDR-CB) is introduced, further refining the model's capability to detect and segment fine airway branches. As a result of these enhancements, the model demonstrates a 11.5% average improvement in segmentation accuracy and connectivity compared to the baseline. The source code is publicly accessible at https://***/inexhaustible419/APMTLAirwaySegment. © 2024 IEEE.

关键词： Pulmonary diseases

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A Model for Jellyfish Detritus Decay through Microbial Processing

A Model for Jellyfish Detritus Decay through Microbial Proce...

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Proceedings of the International Convention MIPRO

作者： Filip Strniša Gregor Kosec “Jožef Stefan” Institute Parallel and Distributed Systems Laboratory Ljubljana Slovenia

The decay of jellyfish blooms introduces a significant organic matter source to the local marine environment that has still an unknown impact on the ecosystem. In recent laboratory experiments, authors studied how the introduction of excess organic material affects the coastal pelagic microbiome by introducing Aurelia aurita detritus to jars of seawater. During these experiments they have monitored bacterial abundance, amino acids' concentrations, dissolved organic carbon, as well the build-up of some inorganic nutrients. They have found, that about half of the protein-rich organic matter in jellyfish detritus is almost instantly available to microbes as dissolved organic matter. Based on this experimental data we devised a mathematical model of the jellyfish proteins (amino acids) degradation caused by marine bacteria. The model is built on top of the Monod bacterial growth model and the Luedeking-Piret metabolite production model. In addition, we incorporated the bacterial populations' age to model the lag phase as well as bacterial decay. In this paper, we demonstrate that with the proposed model, we can sufficiently describe the laboratory measurements. Keywords-bacterial growth; Monod model; Luedeking-Piret model; jellyfish

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