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Evaluation of the GPM-DPR snowfall detection capability: Comparison with CloudSat-CPR

ATMOSPHERIC RESEARCH 2017年 197卷 64-75页

作者： Casella, Daniele Panegrossi, Giulia Sano, Paolo Marra, Anna Cinzia Dietrich, Stefano Johnson, Benjamin T. Kulie, Mark S. CNR Ist Sci Atrnosfera & Clima Rome Italy Serco SPA Frascati Italy Univ Corp Atmospher Res College Pk MD USA NOAA Numer Ctr Weather & Climate Predict Joint Ctr Satellite Data Assimilat College Pk MD USA Michigan Technol Univ Houghton MI 49931 USA

An important objective of the Global Precipitation Measurement (GPM) mission is the detection of falling snow, since it accounts for a significant fraction of precipitation in the mid-high latitudes. The GPM Core Observatory carries the first spaceborne Dual-frequency Precipitation Radar (DPR), designed with enhanced sensitivity to detect lighter liquid and solid precipitation. The primary goal of this study is to assess the DPR's ability to identify snowfall using near-coincident CloudSat Cloud Profiling Radar (CPR) observations and products as an independent reference dataset. CloudSat near global coverage and high sensitivity of the W-band CPR make it very suitable for snowfall-related research. While DPR/CPR radar sensitivity disparities contribute substantially to snowfall detection differences, this study also analyzes other factors such as precipitation phase discriminators that produce snowfall identification discrepancies. Results show that even if the occurrence of snowfall events correctly detected by DPR products is quite small compared to CPR (around 5-7%), the fraction of snowfall mass is not negligible (29-34%). A direct comparison of CPR and DPR reflectivities illustrates that DPR misdetection is worsened by a noise-reducing DPR algorithm component that corrects the measured reflectivity. This procedure eliminates the receiver noise and side lobe clutter effects, but also removes radar signals related to snowfall events that are associated with relatively low reflectivity values. In an effort to increase DPR signal fidelity associated with snowfall, this paper proposes a simple algorithm using matched DPR Ku/Ka radar reflectivities producing an increase of the fraction of snowfall mass detected by DPR up to 59%.

关键词： METEOROLOGICAL precipitation measurement RADAR signal processing PHASE detectors COMPARATIVE studies computer algorithms METEOROLOGICAL stations

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Approach to mine influential functions based on software execution sequence

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IET SOFTWARE 2017年第2期11卷 48-54页

作者： Zhang, Bing Huang, Guoyan He, Haitao Ren, Jiadong Yanshan Univ Coll Informat Sci & Engn Qinhuangdao 066004 Hebei Peoples R China Key Lab Comp Virtual Technol & Syst Integrat Hebe Qinhuangdao 066004 Hebei Peoples R China

In software system, there are some functions of great importance in controlling the whole process of software execution. When they are damaged, the software will suffer from catastrophic consequences caused by cascading failures. To accurately identify and protect these influential functions has become a necessary method in software security. Thus, in this study a new approach to efficiently mine influential functions based on software execution sequence is proposed. First, the authors design a novel modelling strategy by which software execution traces are modelled as sequential patterns. Owing to loops, patterns can occur multiple times in a trace, which leads to high cost of time and extreme complexity of the research. Then, an algorithm is designed to remove repetitive patterns in software and software influential nodes mining algorithm is put forward to mine influential functions in software and to rank them by the rank-index. Finally, by comparatively analysing the topten functions got from PageRank and those from Degree-Based algorithm, the approach is proved to be an effective and accurate one which combines advantages of the two classic algorithms.

关键词： computer software execution DATA mining computer software security measures computer algorithms COMPUTATIONAL complexity

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Min_c: Heterogeneous Concentration Policy for Energy-Aware Scheduling of Jobs with Resource Contention

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PROGRAMMING AND computer SOFTWARE 2017年第3期43卷 204-215页

作者： Armenta-Cano, F. A. Tchernykh, A. Cortes-Mendoza, J. M. Yahyapour, R. Drozdov, A. Yu Bouvry, P. Kliazovich, D. Avetisyan, A. Nesmachnow, S. CICESE Res Ctr Ensenada Baja California Mexico Univ Gottingen Gottingen Germany Moscow Inst Phys & Technol Moscow Russia Univ Luxembourg Luxembourg Luxembourg ISP RAS Moscow Russia Univ Republica Montevideo Uruguay

In this paper, we address energy-aware online scheduling of jobs with resource contention. We propose an optimization model and present new approach to resource allocation with job concentration taking into account types of applications and heterogeneous workloads that could include CPU-intensive, disk-intensive, I/O-intensive, memory-intensive, network-intensive, and other applications. When jobs of one type are allocated to the same resource, they may create a bottleneck and resource contention either in CPU, memory, disk or network. It may result in degradation of the system performance and increasing energy consumption. We focus on energy characteristics of applications, and show that an intelligent allocation strategy can further improve energy consumption compared with traditional approaches. We propose heterogeneous job consolidation algorithms and validate them by conducting a performance evaluation study using the Cloud Sim toolkit under different scenarios and real data. We analyze several scheduling algorithms depending on the type and amount of information they require.

关键词： HETEROGENEOUS computing computer scheduling RESOURCE allocation MATHEMATICAL optimization computer algorithms

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A method of Earth terrain tessellation on the GPU for space simulators

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PROGRAMMING AND computer SOFTWARE 2017年第4期43卷 243-249页

作者： Mikhaylyuk, M. V. Timokhin, P. Y. Maltsev, A. V. Russian Acad Sci Sci Res Inst Syst Anal Nakhimovskii Pr 36-1 Moscow 117218 Russia

This paper presents a new distributed method for virtual Earth terrain tessellation on a graphics processing unit (GPU) for space simulator complexes. The method operates in real time in multi-object virtual scenes comprising up to two million polygons. A polygonal terrain model is constructed using triangle patches of different levels of detail on graphics cards with programmable tessellation. Patches of the same level of detail are calculated entirely on the GPU, in parallel and independently, by using a developed shader program written in the OpenGL Shading Language (GLSL). This paper also describes a patch extraction algorithm for visible Earth surface rendering and an algorithm for correcting the barycentric coordinates of tessellated patch vertices that allows triangles in the terrain model to be docked without geometric discontinuities. Based on the distributed methods and algorithms developed, a program complex for virtual Earth surface visualization was created and successfully tested. The proposed solution can also be employed in virtual environment systems, virtual labs, educational geo-applications, etc.

关键词： GRAPHICS processing units (computers) SPACE simulators computer algorithms BARYCENTRIC dynamical time computer software

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A Novel 3D CAD Model Retrieval Method Based on Vertices Classification and Weights Combination Optimization

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MATHEMATICAL PROBLEMS IN ENGINEERING 2017年第1期2017卷 1-12页

作者： Zhuang, Ting Zhang, Xutang Hou, Zhenxiu Zuo, Wangmeng Liu, Yan Harbin Inst Technol Sch Mechatron Engn Harbin Peoples R China Harbin Inst Technol Sch Comp Sci & Technol Harbin Peoples R China Harbin Inst Technol Sch Sci Harbin Peoples R China

3D shape retrieval is a problem of current interest in different fields, especially in the mechanical engineering domain. According to our knowledge, multifeature based techniques achieve the best performance at present. However, the practicability of those methods is badly limited due to the high computational cost. To improve the retrieval efficiency of 3D CAD model, we propose a novel 3D CAD model retrieval algorithm called VSC-WCO which consists of a new 3D shape descriptor named VSC and Weights Combination Optimization schemeWCO. VSC represents a 3Dmodel with three distance distribution histograms based on vertices classification. The weighted sum of.. 1 norm distances between corresponding distance histograms of two VSC descriptors is regarded as dissimilarity of two models. For higher retrieval accuracy on a classified 3D model database, WCO is proposed based on Particle Swarm Optimization and existing class information. Experimental results on ESB, PSB, and NTU databases show that the discriminative power of VSC is already comparable to or better than several typical shape descriptors. After WCO is employed, the performance of VSC WCO is similar to the leading methods by all performance metrics and is much better by computational efficiency.

关键词： MECHANICAL engineering computer-aided design INFORMATION retrieval MATHEMATICAL optimization computer algorithms

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Tensor-Based Methods for Blind Spatial Signature Estimation in Multidimensional Sensor Arrays

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INTERNATIONAL JOURNAL OF ANTENNAS AND PROPAGATION 2017年第2-15期2017卷 1-11页

作者： Gomes, Paulo R. B. de Almeida, Andre L. F. da Costa, Joao Paulo C. L. Mota, Joao C. M. de Lima, Daniel Valle Del Galdo, Giovanni Univ Fed Ceara Dept Teleinformat Engn Fortaleza Ceara Brazil Univ Brasilia Dept Elect Engn Brasilia DF Brazil Ilmenau Univ Technol Inst Informat Technol Ilmenau Germany Fraunhofer Inst Integrated Circuits IIS Erlangen Germany

The estimation of spatial signatures and spatial frequencies is crucial for several practical applications such as radar, sonar, and wireless communications. In this paper, we propose two generalized iterative estimation algorithms to the case in which a multidimensional (R-D) sensor array is used at the receiver. The first tensor-based algorithm is an R-D blind spatial signature estimator that operates in scenarios where the source's covariance matrix is nondiagonal and unknown. The second tensor-based algorithm is formulated for the case in which the sources are uncorrelated and exploits the dual-symmetry of the covariance tensor. Additionally, a new tensor-based formulation is proposed for an L-shaped array configuration. Simulation results show that our proposed schemes outperform the state-of-the-art matrix-based and tensor-based techniques.

关键词： Multidimensional signal processing Sensor arrays Wireless communication systems computer algorithms Covariance matrices Tensor algebra

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Gradient iterative algorithm for dual-rate nonlinear systems based on a novel particle filter

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JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS 2017年第11期354卷 4425-4437页

作者： Chen, Jing Li, Juan Liu, Yanjun Jiangnan Univ Sch Sci Wuxi 214122 Peoples R China Qingdao Agr Univ Coll Mech & Elect Engn Qingdao 266109 Peoples R China Jiangnan Univ Sch Internet Things Engn Wuxi 214122 Peoples R China

This paper proposes a novel particle filter based gradient iterative algorithm for the identification of dual-rate nonlinear systems. The novel particle filter is applied to estimate the missing outputs, and the measurable outputs are utilized to adjust the weights of particles during each interval of the slow sampled rate. Then the missing outputs and the unknown parameters can be estimated iteratively by the novel particle filter based gradient iterative algorithm. The simulation results indicate that the proposed method is more effective than the classical auxiliary model method. (C) 2017 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

关键词： ITERATIVE methods (Mathematics) computer algorithms NONLINEAR systems MONTE Carlo method SIMULATION methods & models

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Digital Closed-Loop Driving Technique Using the PFD-Based CORDIC Algorithm for a Biaxial Resonant Microaccelerometer

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JOURNAL OF SENSORS 2017年第10-26期2017卷 7861025-7861025页

作者： Yang, Bo Wu, Lei Wang, Binlong Wang, Qiuhua Southeast Univ Sch Instrument Sci & Engn Nanjing 210096 Jiangsu Peoples R China Minist Educ Key Lab Microinertial Instrument & Adv Nav Technol Nanjing 210096 Jiangsu Peoples R China

A digital closed-loop driving technique is presented in this paper that uses the PFD- (phase frequency detector-) based CORDIC (coordinate rotation digital computer) algorithm for a biaxial resonant microaccelerometer. A conventional digital closed-loop self-oscillation system based on the CORDIC algorithm is implemented and simulated using Simulink software to verify the system performance. The system performance simulations reveal that the incompatibility between the sampling frequency and effective bits of AD and DA convertors limits further performance improvements. Therefore, digital, closed-loop self-oscillation using the PFD-based CORDIC algorithm is designed to further optimize the system performance. The system experimental results illustrate that the optimized system using the PFD-based CORDIC improves the bias stability of the resonant micro accelerometer by more than 5.320 times compared to the conventional system. This demonstrates that the optimized digital closed-loop driving technique using the PFD-based CORDIC for the biaxial resonant microaccelerometer is effective.

关键词： Detectors Digital technology Closed loop systems computer algorithms

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Efficient Enhancement for Spatial Scalable Video Coding Transmission

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MATHEMATICAL PROBLEMS IN ENGINEERING 2017年第1期2017卷 1-13页

作者： Khairy, Mayada Hamdy, Alaa Elsayed, Amr Farouk, Hesham Elect Res Inst Dept Comp & Syst Giza Egypt Helwan Univ Elect Commun & Comp Dept Cairo Egypt

Scalable Video Coding (SVC) is an international standard technique for video compression. It is an extension of H. 264 Advanced Video Coding (AVC). In the encoding of video streams by SVC, it is suitable to employ the macroblock (MB) mode because it affords superior coding efficiency. However, the exhaustive mode decision technique that is usually used for SVC increases the computational complexity, resulting in a longer encoding time (ET). Many other algorithms were proposed to solve this problem with imperfection of increasing transmission time (TT) across the network. To minimize the ET and TT, this paper introduces four efficient algorithms based on spatial scalability. The algorithms utilize the mode-distribution correlation between the base layer (BL) and enhancement layers (ELs) and interpolation between the EL frames. The proposed algorithms are of two categories. Those of the first category are based on interlayer residual SVC spatial scalability. They employ two methods, namely, interlayer interpolation (ILIP) and the interlayer base mode (ILBM) method, and enable ET and TT savings of up to 69.3% and 83.6%, respectively. The algorithms of the second category are based on full-search SVC spatial scalability. They utilize two methods, namely, full interpolation (FIP) and the full-base mode (FBM) method, and enable ET and TT savings of up to 55.3% and 76.6%, respectively.

关键词： VIDEO coding (computer science) DATA transmission systems SCALABILITY (Systems engineering) COMPUTATIONAL complexity computer algorithms

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A New Terrain Classification Framework Using Proprioceptive Sensors for Mobile Robots

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MATHEMATICAL PROBLEMS IN ENGINEERING 2017年第1期2017卷 1-14页

作者： Zhao, Kai Dong, Mingming Gu, Liang Beijing Inst Technol Sch Mech Engn Beijing 100081 Peoples R China

Mobile robots that operate in real-world environments interact with the surroundings to generate complex acoustics and vibration signals, which carry rich information about the terrain. This paper presents a new terrain classification framework that utilizes both acoustics and vibration signals resulting from the robot-terrain interaction. As an alternative to handcrafted domain-specific feature extraction, a two-stage feature selection method combining ReliefF and mRMR algorithms was developed to select optimal feature subsets that carry more discriminative information. As different data sources can provide complementary information, a multi-classifier combination method was proposed by considering a priori knowledge and fusing predictions from five data sources: one acoustic data source and four vibration data sources. In this study, four conceptually different classifiers were employed to perform the classification, each with a different number of optimal features. Signals were collected using a tracked robot moving at three different speeds on six different terrains. The new framework successfully improved classification performance of different classifiers using the newly developed optimal feature subsets. The greater improvement was observed for robot traversing at lower speeds.

关键词： PROPRIOCEPTION MOBILE robots VIBRATION (Mechanics) FEATURE selection (Machine learning) computer algorithms

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