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SU-C-207A-06: On-Line Beam Range Verification with Multiple Scanning Particle Beams: Initial Feasibility Study with Simulations

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Medical Physics 2016年第6PART3期43卷 3325-3325页

作者： Y Zhong X Sun W Lu X Jia J Wang Y Shao The University of Texas Southwestern Medical Ctr. Dallas TX

Purpose: To investigate the feasibility and requirement for intra-fraction on-line multiple scanning particle beam range verifications (BRVs) with in-situ PET imaging, which is beyond the current single-beam BRV with extra factors that will affect the BR measurement accuracy, such as beam diameter, separation between beams, and different image counts at different BRV positions. methods: We simulated a 110-MeV proton beam with 5-mm diameter irradiating a uniform PMMA phantom by GATE simulation, which generated nuclear interaction-induced positrons. In this preliminary study, we simply duplicated these positrons and placed them next to the initial protons to approximately mimic the two spatially separated positron distributions produced by two beams parallel to each other but with different beam ranges. These positrons were then imaged by a PET (∼2-mm resolution, 10% sensitivity, 320×320×128 mm^3 FOV) with different acquisition times. We calculated the positron activity ranges (ARs) from reconstructed PET images and compared them with the corresponding ARs of original positron distributions. Results: Without further image data processing and correction, the preliminary study show the errors between the measured and original ARs varied from 0.2 mm to 2.3 mm as center-to-center separations and range differences were in the range of 8–12 mm and 2–8 mm respectively, indicating the accuracy of AR measurement strongly depends on the beam separations and range differences. In addition, it is feasible to achieve ≤ 1.0-mm accuracy for both beams with 1-min PET acquisition and 12 mm beam separation. Conclusion: This study shows that the overlap between the positron distributions from multiple scanning beams can significantly impact the accuracy of BRVs of distributed particle beams and need to be further addressed beyond the established method of single-beam BRV, but it also indicates the feasibility to achieve accurate on-line multi-beam BRV with further improved method.

关键词： Positron beams Positrons Positron emission tomography image reconstruction Protons Electric measurements Spatial dimensions Nuclear interactions Data processing

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The framework of P systems applied to solve optimal watermarking problem

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SIGNAL processing 2014年 101卷 256-265页

作者： Peng, Hong Wang, Jun Perez-Jimenez, Mario J. Riscos-Nunez, Agustin Xihua Univ Ctr Radio Adm & Technol Dev Chengdu 610039 Peoples R China Xihua Univ Sch Elect & Informat Engn Chengdu 610039 Peoples R China Univ Seville Dept Comp Sci & Artificial Intelligence Res Grp Nat Comp E-41012 Seville Spain

Membrane computing (known as P systems) is a novel class of distributed parallel computing models inspired by the structure and functioning of living cells and organs, and its application to the real-world problems has become a hot topic in recent years. This paper discusses an interesting open problem in digital watermarking domain, optimal watermarking problem, and proposes a new optimal image watermarking method under the framework of P systems. A special membrane structure is designed and its cells as parallel computing units are used to find the optimal watermarking parameters for image blocks. Some cells use the position-velocity model to evolve watermarking parameters of image blocks, while another cell evaluates the objects in the system. In addition to the evolution rules, communication rules are used to exchange and share information between the cells. Simulation experiments on large image set compare the proposed framework with other existing watermarking methods and demonstrate its superiority. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Membrane computing P systems image watermarking Optimal watermarking problem

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HNCP-ii: A 16-core 65nm microprocessor ASIC for image processing algorithms

HNCP-II: A 16-core 65nm microprocessor ASIC for image proces...

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9th International Symposium on Reconfigurable and Communication-Centric Systems-on-Chip (ReCoSoC)

作者： Boussadi, Mohamed Amine Tixier, Thierry Landrault, Alexis Derutin, Jean-Pierre Inst Pascal UMR 6602 CNRS UBP IFMA F-63171 Aubiere France

ISBN: (纸本)9781479958108

In many video and image processing applications, complexity has reached a point where the performance requirements can no longer be supported by standard architectures based on a single processor. This is why many systems are based on multiprocessor architecture. In this paper, we present HNCP-ii a 16-core flexible distributed memory ASIC dedicated to embedded application field (image processing applications). Connected through a torus on-chip network, each tile of the overall system includes an open-source RISC processor, a floating point unit, a video management module and a set of built in hardware features for multicore communication. This specific hardware enables to meet most relevant overall parallelism scheme (parallel skeletons) thanks to software-configurable modules. Results are presented for two image processing algorithms in term of execution time, speedup and efficiency. Area, power and timing performance of the synthesized ASIC are given for a CMOS 65nm technology node.

关键词： image processing algorithm network-on-chip application specific integrated circuits ASIC Uniprocessor Tile toruses macroprocessor MULTIPROCESSOR ARCHITECTURE

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parallelization of searching and mining time series data using Dynamic Time Warping

Parallelization of searching and mining time series data usi...

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International Conference on Advances in Computing, Communications and Informatics (ICACCI)

作者： Ahmed Shabib Anish Narang Chaitra Prasad Niddodi Madhura Das Rachita Pradeep Varun Shenoy Prafullata Auradkar Vignesh TS Dinkar Sitaram Dept. of Computer Science and Engineering PES Institute of Technology Bangalore India

Among the various algorithms present for data mining, the UCR Dynamic Time Warping (DTW) suite provided a solution to search and mine large data sets of time series data more efficiently as compared to the previously existing method of using Euclidean Distance. The UCR DTW algorithm was developed for a single CPU core. In this paper, we consider 2 methods of parallelizing the DTW algorithm. First, we consider a multi-core implementation, followed by a cluster implementation using Spark. From the multi-core implementation, we achieve nearly linear speedup. In the Spark implementation, we find that a straightforward implementation of DTW does not perform well. This is because; a major step in DTW is parallel computation of a lower bound. This paradigm is not supported well by Spark, which supports (i) broadcast variables that are broadcasts of read-only variables (ii) accumulation variables that represent distributed sums. We show how to compute distributed lower bounds efficiently in Spark and achieve nearly linear speedup with DTW in a Spark computation as well.

关键词： Instruction sets Sparks Time series analysis Multicore processing Algorithm design and analysis Clustering algorithms Random access memory

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Evaluation of a Sector-Hash Based Rapid File Detection Method for Monitoring Infrastructure-as-a-Service Cloud Platforms

Evaluation of a Sector-Hash Based Rapid File Detection Metho...

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International Conference on Availability, Reliability and Security, ARES

作者： Manabu Hirano Hayate Takase Koki Yoshida Department of Information and Computer Engineering National Institute of Technology Japan

Current computer forensics tools have some limitations on anti-forensics attacks, cloud computing, and a large increase in the size of forensics targets. To solve these problems, this paper proposes a system that preserves storage data on virtual machines by acquiring all data sectors with time stamps. The proposed system can restore a previous state of a block device at any date and time that is specified by an investigator. The proposed system aims to monitor users' behavior in Infrastructure-as-a-Service (IaaS) cloud platforms. This paper also presents a rapid file detection system that finds a target file from a large collection of the acquired data sectors by using sector-hashes and parallel distributed processing. This system enables investigators to track and to find a target file that is related to incidents or crimes in the cloud. First, this paper reports the preliminary experiments of a sector-hash based file detection method on three major operating systems for evaluating its effectiveness. We present a design and an implementation of the proposed monitoring and target file detection system by using Xen hypervisor and MapReduce. We report results of its performance evaluation. Finally, we discuss possible methods to improve the performance and the limitations of the current proposed mechanism.

关键词： Forensics Computers Monitoring image restoration distributed databases File systems Cloud computing

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基於田口法與FPGA平行運算辨識物件顏色之影像處理

基於田口法與FPGA平行運算辨識物件顏色之影像處理

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作者：李彥儀虎尾科技大學

学位级别：碩士

本论文研究主要目的为运用田口统计分析与FPGA(Field programmable gate array)平行运算平台，进行分析不同物件颜色之影像辨识与处理。FPGA硬体平台使用DE2-115发展板，其内含处理器为Altera Cyclone IV的FPGA晶片，并利用其平行机制... 详细信息

本论文研究主要目的为运用田口统计分析与FPGA(Field programmable gate array)平行运算平台，进行分析不同物件颜色之影像辨识与处理。FPGA硬体平台使用DE2-115发展板，其内含处理器为Altera Cyclone IV的FPGA晶片，并利用其平行机制的特性，於每时脉循环可同时完成多重平行运算作业，因此超越数位讯号处理器(Digital signal processor，简称DSP)的计算速度，硬体层级控制Input/Output(I/O)与其他硬体比较更可缩短响应时间。物件颜色阀值方面则是以Red/Green/Blue(RGB)空间为色域基础，并将整体影像转为二值化以利於分离目标色彩与其它色彩，本实验以Red、Green及Blue的物件作为辨识目标，并透过各物件有效像素色彩值的统计，接着使用田口品质方法将辨识阀值上调与下调一定的裕度後，排列成全因子的形式并再度重新进行最佳化色彩辨识，以探讨是否提高物件辨识的精准度。最後尝试将全因子的排列方式写入FPGA平台，并将阀值的有效像素值显示於七段显示器上，与依照色码表所找出的手动阀值辨识结果做比对及验证，且使用田口品质方法进行S/N比以及变异数分析的运算，找出各因子所造成的贡献度。所有影像部分皆以VGA或是VEEK-MT作为输出平台；程式方面使用Quartus ii 11.1进行编译，而硬体描述语言部份则是使用Verilog HDL的方式来实现以上的方法；田口品质方法以望大型来计算有效像素值的S/N信号杂音比。变异数分析红色物件的辨识结果，最佳化组合为R1G3B2，主要趋势影响最大的是B因子，贡献度也是B因子较多为78.73824%，误差比例为8.472%；绿色物件的最佳化组合为R2G1B3，主要趋势影响最大的是G因子，其贡献度也最多为62.44788%，误差比例为8.626%；蓝色物件的最佳化组合为R3G3B3，影响主要趋势最高的也是G因子，贡献度为36.40271%，但其误差高达35.018%

关键词： FPGA 平行運算影像處理田口品質方法最佳化分析

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A Comparative Study on Interpolation methods in Rebinning Circular Fan-beam data into parallel-beam data

A Comparative Study on Interpolation Methods in Rebinning Ci...

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27th IEEE International Symposium on Computer-Based Medical Systems (CBMS)

作者： Ryu, Sunsik Back, Jongduk Yonsei Univ Yonsei Inst Convergence Technol Inchon South Korea

ISBN: (纸本)9781479944354

Computed Tomography (CT) scanners evolved from simple parallel-beam geometry into more complex fan-beam geometry. The rebinning mechanism to convert fan-beam projections to parallel-beam projections is one of the methods simplifying the reconstruction of the CT image. Various interpolation methods result in different numerical presentations and noisy textures in the reconstructed CT images. This paper evaluates three interpolation methods, linear, frequency domain and higher order in rebinning fan-beam data into parallel-beam data in the framework of the FBP algorithm in parallel-beam CTs. The high-contrast spatial resolution, modulation transfer function (MTF), and noise are used to quantify the image quality. The noise is expressed as the noise power spectrum (NPS) and noise variance of the reconstructed image containing only Poisson distributed noise. Our results show that the higher order interpolation, cubic-spline, is the most helpful to improve the image quality in rebinning. We further demonstrate that the rebinning data gives more satisfactory results for assessment of noise variance in comparison with the fan-beam data.

关键词： image processing x-ray CT rebinning MTF interpolation

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Towards a performance-portable description of geometric multigrid algorithms using a domain-specific language

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JOURNAL OF parallel AND distributed COMPUTING 2014年第12期74卷 3191-3201页

作者： Membarth, Richard Reiche, Oliver Schmitt, Christian Hannig, Frank Teich, Juergen Stuermer, Markus Koestler, Harald German Res Ctr Artificial Intelligence Saarbrucken Germany Univ Saarland Comp Graph Lab D-66123 Saarbrucken Germany Univ Saarland Intel Visual Comp Inst D-66123 Saarbrucken Germany Univ Erlangen Nurnberg Dept Comp Sci Nurnberg Germany

High Performance Computing (HPC) systems are nowadays more and more heterogeneous. Different processor types can be found on a single node including accelerators such as Graphics processing Units (GPUs). To cope with the challenge of programming such complex systems, this work presents a domain-specific approach to automatically generate code tailored to different processor types. Low-level CUDA and OpenCL code is generated from a high-level description of an algorithm specified in a Domain-Specific Language (DSL) instead of writing hand-tuned code for GPU accelerators. The DSL is part of the Heterogeneous image processing Acceleration (HIPA(cc)) framework and was extended in this work to handle grid hierarchies in order to model different cycle types. Language constructs are introduced to process and represent data at different resolutions. This allows to describe image processing algorithms that work on image pyramids as well as multigrid methods in the stencil domain. By decoupling the algorithm from its schedule, the proposed approach allows to generate efficient stencil code implementations. Our results show that similar performance compared to hand-tuned codes can be achieved. (C) 2014 Elsevier Inc. All rights reserved.

关键词： Multigrid Multiresolution image pyramid Domain-specific language Stencil codes Code generation GPU CUDA OpenCL

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Decomposition by Partial Linearization: parallel Optimization of Multi-Agent Systems

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IEEE TRANSACTIONS ON SIGNAL processing 2014年第3期62卷 641-656页

作者： Scutari, Gesualdo Facchinei, Francisco Song, Peiran Palomar, Daniel P. Pang, Jong-Shi SUNY Buffalo Dept Elect Engn Buffalo NY 14260 USA Univ Roma La Sapienza Dept Comp Control & Management Engn I-00185 Rome Italy Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Hong Kong Hong Kong Peoples R China Univ So Calif Viterbi Sch Engn Dept Ind & Syst Engn Los Angeles CA 90089 USA

We propose a novel decomposition framework for the distributed optimization of general nonconvex sum-utility functions arising naturally in the system design of wireless multi-user interfering systems. Our main contributions are i) the development of the first class of (inexact) Jacobi best-response algorithms with provable convergence, where all the users simultaneously and iteratively solve a suitably convexified version of the original sum-utility optimization problem;ii) the derivation of a general dynamic pricing mechanism that provides a unified view of existing pricing schemes that are based, instead, on heuristics;and iii) a framework that can be easily particularized to well-known applications, giving rise to very efficient practical (Jacobi or Gauss-Seidel) algorithms that outperform existing ad hoc methods proposed for very specific problems. Interestingly, our framework contains as special cases well-known gradient algorithms for nonconvex sum-utility problems, and many block-coordinate descent schemes for convex functions.

关键词： Nonconvex multi-agent problems parallel and distributed optimization successive convex approximation

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Analysis of Partitioning Models and Metrics in parallel Sparse Matrix-Vector Multiplication 1

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10th International Conference on parallel processing and Applied Mathematics (PPAM)

作者： Kaya, Kamer Ucar, Bora Catalyuerek, Uemit V. CNRS Lyon France

ISBN: (数字)9783642551956

ISBN: (纸本)9783642551956

Graph/hypergraph partitioning models and methods have been successfully used to minimize the communication among processors in several parallel computing applications. parallel sparse matrix-vector multiplication (SpMxV) is one of the representative applications that renders these models and methods indispensable in many scientific computing contexts. We investigate the interplay of the partitioning metrics and execution times of SpMxV implementations in three libraries: Trilinos, PETSc, and an in-house one. We carry out experiments with up to 512 processors and investigate the results with regression analysis. Our experiments show that the partitioning metrics influence the performance greatly in a distributed memory setting. The regression analyses demonstrate which metric is the most influential for the execution time of the libraries.

关键词： parallel sparse-matrix vector multiplication Hypergraph partitioning

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