Blar i forfatter "Ha, Hoai Phuong"

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    • Access control protocol with node privacy in wireless sensor networks 

      Kumar, Pardeep; Gurtov, Andrei; Iinatti, Jari; Sain, Mangal; Ha, Hoai Phuong (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-15)
      For preventing malicious nodes joining wireless sensor networks (WSNs), an access control mechanism is necessary for the trustworthy cooperation between the nodes. In addition to access control, recently, privacy has been an important topic regarding how to achieve privacy without disclosing the real identity of communicating entities in the WSNs. Based on elliptic curve cryptography, in this paper, ...

    • Accurate Lightweight Calibration Methods for Mobile Low-Cost Particulate Matter Sensors 

      Jørstad, Per Martin; Wojcikowski, Marek; Cao, Tuan-Vu; Lepioufle, Jean-Marie; Wojtkiewicz, Krystian; Ha, Hoai Phuong (Chapter; Bokkapittel, 2023-09-05)
      <p>Monitoring air pollution is a critical step towards improving public health, particularly when it comes to identifying the primary air pollutants that can have an impact on human health. Among these pollutants, particulate matter (PM) with a diameter of up to 2.5 μm (or PM2.5) is of particular concern, making it important to continuously and accurately monitor pollution related to PM. The emergence ...

    • DeltaTree: A Locality-aware Concurrent Search Tree 

      Umar, Ibrahim; Anshus, Otto; Ha, Hoai Phuong (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-15)
      Like other fundamental abstractions for high-performance computing, search trees need to support both high concurrency and data locality. However, existing locality-aware search trees based on the van Emde Boas layout (vEB-based trees), poorly support concurrent (update) operations. We present DeltaTree, a practical locality-aware concurrent search tree that integrates both locality-optimization ...

    • DeltaTree: A Practical Locality-aware Concurrent Search Tree 

      Umar, Ibrahim; Anshus, Otto; Ha, Hoai Phuong (Research report; Forskningsrapport, 2013)
      As other fundamental programming abstractions in energy-e cient computing, search trees are expected to support both high parallelism and data locality. However, existing highly-concurrent search trees such as red-black trees and AVL trees do not consider data locality while existing locality-aware search trees such as those based on the van Emde Boas layout (vEB-based trees), poorly support ...

    • Efficient concurrent search trees using portable fine-grained locality 

      Ha, Hoai Phuong; Anshus, Otto; Umar, Ibrahim (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-14)
      Concurrent search trees are crucial data abstractions widely used in many important systems such as databases, file systems and data storage. Like other fundamental abstractions for energy-efficient computing, concurrent search trees should support both high concurrency and fine-grained data locality in a platform-independent manner. However, existing portable fine-grained locality-aware search trees ...

    • Evaluation of the power efficiency of UPC, OpenMP and MPI 

      Lagraviere, Jeremie; Ha, Hoai Phuong; Cai, Xing (Research report; Forskningsrapport, 2015)
      In this study we compare the performance and power efficiency of Unified Parallel C (UPC), MPI and OpenMP by running a set of kernels from the NAS Benchmark. One of the goals of this study is to focus on the Partitioned Global Address Space (PGAS) model, in order to describe it and compare it to MPI and OpenMP. In particular we consider the power effi- ciency expressed in millions operations ...

    • Experimental Fault-Tolerant Synchronization for Reliable Computation on Graphics Processors 

      Hagen, Tor-Magne Stien; Ha, Hoai Phuong; Anshus, Otto (Research report; Forskningsrapport, 2012)
      Graphics processors (GPUs) are emerging as a promising platform for highly parallel, compute-intensive, general-purpose computations, which usually need support for inter-process synchronization. Using the traditional lock-based synchronization (e.g. mutual exclusion) makes the computation vulnerable to faults caused by both scientists’ inexperience and hardware transient errors. It is notoriously ...

    • GreenBST: Energy-efficient concurrent search tree 

      Umar, Ibrahim; Anshus, Otto; Ha, Hoai Phuong (Conference object; Konferansebidrag, 2016-08-09)
      Like other fundamental abstractions for energy-efficient com- puting, search trees need to support both high concurrency and fine- grained data locality. However, existing locality-aware search trees such as ones based on the van Emde Boas layout (vEB-based trees), poorly support concurrent (update) operations while existing highly-concurrent search trees such as the non-blocking binary search ...

    • Highly efficient and scalable framework for high-speed super-resolution microscopy 

      Do, Quan; Acuña Maldonado, Sebastian Andres; Kristiansen, Jon Ivar; Agarwal, Krishna; Ha, Hoai Phuong (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-05)
      The multiple signal classification algorithm (MUSICAL) is a statistical super-resolution technique for wide-field fluorescence microscopy. Although MUSICAL has several advantages, such as its high resolution, its low computational performance has limited its exploitation. This paper aims to analyze the performance and scalability of MUSICAL for improving its low computational performance. We first ...

    • Implementing and optimizing a Sparse Matrix-Vector Multiplication with UPC 

      Lagraviere, Jeremie Alexandre Emilien; Prugger, Martina; Einkemmer, Lukas; Langguth, Johannes; Ha, Hoai Phuong; Cai, Xing (Research report; Forskningsrapport, 2016)
      Programmability and performance-per-watt are the major challenges of the race to Exascale. In this study we focus on Partitioned Global Address Space (PGAS) languages, using UPC as a particular example. This category of parallel languages provides ease of programming as a strong advantage over the classic Message Passing Interface(MPI). PGAS has also advantages compared to classic shared memory ...

    • Masking the Effects of Delays in Human-to-Human Remote Interaction 

      Su, Fei; Bjørndalen, John Markus; Ha, Hoai Phuong; Anshus, Otto (Chapter; Bokkapittel, 2014)
      Humans can interact remotely with each other through computers. Systems supporting this include teleconferencing, games and virtual environments. There are delays from when a human does an action until it is reflected remotely. When delays are too large, they will result in inconsistencies in what the state of the interaction is as seen by each participant. The delays can be reduced, but they cannot ...

    • Models for energy consumption of data structures and algorithms 

      Ha, Hoai Phuong; Tran, Ngoc Nha Vi; Umar, Ibrahim; Tsigas, Philippas; Gidenstam, Anders; Renaud-Goud, Paul; Walulya, Ivan; Atalar, Aras (Research report; Forskningsrapport, 2014)
      This deliverable reports our early energy models for data structures and algorithms based on both micro-benchmarks and concurrent algorithms. It reports the early results of Task 2.1 on investigating and modeling the trade-off between energy and performance in concurrent data structures and algorithms, which forms the basis for the whole work package 2 (WP2). The work has been ...

    • MultiStage: Acting across Distance 

      Su, Fei; Tartari, Giacomo; Bjørndalen, John Markus; Ha, Hoai Phuong; Anshus, Otto (Conference object; Konferansebidrag, 2013)
      We report on a prototype system helping actors on a stage to interact and perform with actors on other stages as if they were on the same stage. At each stage four 3D cameras tiled back to back for an almost 360 degree view, continuously record actors. The system processes the recorded data on-the-fly to discover actions by actors that it should react to, and it streams data about actors and their ...

    • NB-FEB : an easy-to-use and scalable universal synchronization primitive for parallel programming 

      Ha, Hoai Phuong; Tsigas, Philippas; Anshus, Otto J. (Research report; Forskningsrapport, 2008-10)
      This paper addresses the problem of universal synchronization primitives that can support scalable thread synchronization for large-scale many-core architectures. The universal synchronization primitives that have been deployed widely in conventional architectures, are the compare-and-swap (CAS) and load-linked/store-conditional (LL/SC) primitives. However, such synchronization primitives are ...

    • On the performance and energy efficiency of the PGAS programming model on multicore architectures 

      Lagraviere, Jeremie Alexandre Emilien; Langguth, Johannes; Sourouri, Mohammed; Ha, Hoai Phuong; Cai, Xing (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-15)

    • Performance optimization and modeling of fine-grained irregular communication in UPC 

      Lagraviere, Jeremie Alexandre Emilien; Langguth, Johannes; Prugger, Martina; Einkemmer, Lukas; Ha, Hoai Phuong; Cai, Xing (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-03)
      The Unified Parallel C (UPC) programming language offers parallelism via logically partitioned shared memory, which typically spans physically disjoint memory subsystems. One convenient feature of UPC is its ability to automatically execute between-thread data movement, such that the entire content of a shared data array appears to be freely accessible by all the threads. The programmer friendliness, ...

    • Power models, energy models and libraries for energy-efficient concurrent data structures and algorithms 

      Ha, Hoai Phuong; Tran, Vi Ngoc-Nha; Umar, Ibrahim; Atalar, Aras; Gidenstam, Anders; Renaud-Goud, Paul; Tsigas, Philippas; Walulya, Ivan (Research report; Forskningsrapport, 2016)
      This deliverable reports the results of the power models, energy models and librariesfor energy-efficient concurrent data structures and algorithms as available by projectmonth 30 of Work Package 2 (WP2). It reports i) the latest results of Task 2.2-2.4 onproviding programming abstractions and libraries for developing energy-efficient datastructures and algorithms and ii) the improved results of ...

    • pVD - Personal Video Distribution 

      Su, Fei; Bjørndalen, John Markus; Ha, Hoai Phuong; Anshus, Otto (Journal article; Tidsskriftartikkel, 2013-11-25)
      A user has several personal computers, including mobile phones, tablets, and laptops, and needs to watch live camera feeds from and videos stored at any of these computers at one or more of the others. Industry solutions designed for many users, computers, and videos can be complicated and slow to apply. The user must typically rely on a third party service or at least log in. The Personal Video ...

    • Real-Time Change Detection with Convolutional Density Approximation 

      Ha, Synh Viet-Uyen; Nguyen, Tien Cuong; Phan, Hung Ngoc; Ha, Hoai Phuong (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-02)
      Background Subtraction (BgS) is a widely researched technique to develop online Change Detection algorithms for static video cameras. Many BgS methods have employed the unsupervised, adaptive approach of Gaussian Mixture Model (GMM) to produce decent backgrounds, but they lack proper consideration of scene semantics to produce better foregrounds. On the other hand, with considerable computational ...

    • Report on the final prototype of programming abstractions for energy-efficient inter-process communication 

      Ha, Hoai Phuong; Tran, Vi Ngoc-Nha; Umar, Ibrahim; Atalar, Aras; Gidenstam, Anders; Renaud-Goud, Paul; Tsigas, Philippas; Walulya, Ivan (Research report; Forskningsrapport, 2016)
      Work package 2 (WP2) aims to develop libraries for energy-efficient inter-processcommunication and data sharing on the EXCESS platforms. The Deliverable D2.4reports on the final prototype of programming abstractions for energy-efficient inter-process communication. Section 1 is the updated overview of the prototype of pro-gramming abstraction and devised power/energy models. The Section 2-6 contain ...