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Search Results: 1 - 10 of 44649 matches for " Peng Hu "
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LA-ICP-MS Calibrations for Intact Rock Samples with Internal Standard and Modified Constant-Sum Methods  [PDF]
Sheng Peng, Qinhong Hu
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.32024
Abstract: Laser ablation coupled with inductively coupled plasma-mass spectrometry (LA-ICP-MS) calibration was conducted with multiple spot analyses on eleven intact rock samples using both an internal standard (IS) method and a modified constant-sum (MCS) method. Methods were then compared for reported bulk elemental composition of the rocks. The MCS method was based on the sum of eight major elements, which is spatially more stable than one single major ele-ment as used in the IS method, and is quite constant among different rock samples. Calibrations were performed with standard reference materials NIST SRM 610, 612, 614, and 616. Little difference was found between using a single standard and a set of standards, because of the good linearity shown by the reference materials. Comparison of the two calibration methods shows that the MCS method produced better and more stable results than the IS method for heterogeneous samples. With the MCS method, approximately 94% to 95% of the total measurements are within the range of ±100% relative deviation, compared with 82% to 86% with the IS method. The IS method resulted insubstantial overestimations for some rock samples (e.g., 648% for Basalt BCR-2 using NIST SRM 610 as the calibration standard), while the largest deviation with the MCS method was 216% for U in Eagle Ford shale #80 sample. For Quartz latite QLO-1, a relative homogeneous sample, the IS method generated slightly better results than the MCS method. Regardless of method, spatially heterogeneous distribution of elements in the intact rock at the scale of the laser spot is considered to be the main reason for the large relative deviations seen in our work compared to published results.
A System Architecture for Software-Defined Industrial Internet of Things
Peng Hu
Computer Science , 2015,
Abstract: Wireless sensor networks have been a driving force of the Industrial Internet of Things (IIoT) advancement in the process control and manufacturing industry. The emergence of IIoT opens great potential for the ubiquitous field device connectivity and manageability with an integrated and standardized architecture from low-level device operations to high-level data-centric application interactions. This technological development requires software definability in the key architectural elements of IIoT, including wireless field devices, IIoT gateways, network infrastructure, and IIoT sensor cloud services. In this paper, a novel software-defined IIoT (SD-IIoT) is proposed in order to solve essential challenges in a holistic IIoT system, such as reliability, security, timeliness scalability, and quality of service (QoS). A new IIoT system architecture is proposed based on the latest networking technologies such as WirelessHART, WebSocket, IETF constrained application protocol (CoAP) and software-defined networking (SDN). A new scheme based on CoAP and SDN is proposed to solve the QoS issues. Computer experiments in a case study are implemented to show the effectiveness of the proposed system architecture.
A Novel Coordinated Sliding Mode Controller Based on Lyapunov Method for SVC, Excitation and Steam Valving  [PDF]
Jiwei Du, Hu Peng, Ben Wang
Energy and Power Engineering (EPE) , 2012, DOI: 10.4236/epe.2012.46065
Abstract: A novel coordinated controller is proposed in the paper for SVC, excitation and steam valving for a single machine infinite system. Firstly, the nonlinear mathematic model of the system including the itation and steam valving is exactly linearized via state feedback. Then, the quasi-linearized system after the exact lineariztion is controlled by the sliding model controller based on Lyapunov direct method. At last, the novel coordinated controller is compared with a traditional linear controller and a nonlinear optimal controller respectively by simulations. The simulation results show that the proposed controller gives better dynamic response and stronger robustness.
Segmentation of Hyper-Acute Ischemic Infarcts from Diffusion Weighted Imaging Based on Support Vector Machine  [PDF]
Yuqing Peng, Xiaodong Zhang, Qingmao Hu
Journal of Computer and Communications (JCC) , 2015, DOI: 10.4236/jcc.2015.311024

Accurate and automatic segmentation of hyper-acute ischemic infarct from magnetic resonance imaging is of great importance in clinical trials. Manual delineation is labor intensive, exhibits great variability due to unclear infarct boundaries, and most importantly, is not practical due to urgent time requirement for prompt therapy. In this paper, segmentation of hyper-acute ischemic infarcts from diffusion weighted imaging based on Support Vector Machine (SVM) is explored. Experiments showed that SVM could provide good agreement with manual delineations by experienced experts to achieve an average Dice coefficient of 0.7630.121. The proposed method could achieve significantly higher segmentation accuracy and could be a potential tool to assist clinicians for quantifying hyper-acute infarction and decision making especially for thrombolytic therapy.

A Consensus-Based Protocol for Spectrum Sharing Fairness in Cognitive Radio Ad Hoc and Sensor Networks
Peng Hu,Mohamed Ibnkahla
International Journal of Distributed Sensor Networks , 2012, DOI: 10.1155/2012/370251
Abstract: Spectrum sharing fairness is an important topic in cognitive radio ad hoc networks (CRAHNs) and cognitive radio sensor networks (CRSNs). Consensus-based protocols can provide light-weight and efficient solutions for CRAHNs and CRSNs but the theoretical ground needs to be investigated for spectrum sharing fairness. In this paper, we investigate the convergence condition when applying a consensus-based protocol to spectrum sharing while ensuring spectrum sharing fairness. Based on the local observation and local control scheme using spectrum-related information, an individual cognitive node can effectively perform the spectrum sharing. Then we propose a consensus-based protocol for spectrum sharing. Supported with computer simulation results, we show the effectiveness of using the proposed consensus-based protocol to solve the spectrum sharing problems in CRAHNs and CRSNs. 1. Introduction As a result of the development of cognitive radio (CR) technology, the concept of cognitive radio ad hoc networks (CRAHNs) has been proposed in 2009 [1]. A CRAHN is essentially an ad hoc network composed by CR nodes (or CRs) and primary users (PUs) applying the cognitive radio technology in CR transceivers. As such, the CRs in CRAHNs do not favor central coordination when performing spectrum sharing processes. Instead, CRs have to perform local observation most of the time. With the same concept, the cognitive radio sensor network (CRSN) [2] was coined out in 2009, where each sensor node in a CRSN can be considered as a CR with limited hardware and capability to obtain surrounding information. As an important research topic in CRAHNs and CRSNs, spectrum sharing schemes have to perform spectrum allocation based on local observations, while ensuring fairness in these schemes. Without keeping fairness, the network may suffer from uneven spectrum allocation to the CRs, subject to the frequent link disconnections during data communications. As such, an important problem in spectrum sharing is how to ensure the fairness of spectrum allocation using local observation and local decision. In this paper, we explore how to use the consensus protocol to address spectrum sharing fairness in CRAHNs and CRSNs. We will first introduce the concept of local control schemes, by which a CR can locally perform spectrum sharing process with sensing inputs and decision outputs. Then we define and analyze the spectrum sharing fairness issue in CRAHNs. Based on this analysis, we propose a consensus-based protocol to perform the spectrum sharing process, which can address the defined fairness
Piperazine-1,4-diium bis(perchlorate) dihydrate
Cong-hu Peng
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810030345
Abstract: The asymmetric unit of the title compound, C4H12N22+·2ClO4 ·2H2O, contains half of a piperazinediium cation, one perchlorate anion and one water molecule. The diprotonated piperazine ring, which is completed by crystallographic inversion symmetry, adopts a chair conformation. In the crystal structure, the cations and anions are linked by intermolecular N—H...O and O—H...O hydrogen bonds into a three-dimensional network.
Trusted e-Commerce User Agent Based on USB Key
Dawei Zhang,Peng Hu
Lecture Notes in Engineering and Computer Science , 2008,
Bis(1-methylpiperazine-1,4-diium) tetrabromidocuprate(II)
Cong-hu Peng
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811024184
Abstract: The title compound, (C5H14N2)[CuBr4], was synthesized by hydrothermal reaction of CuBr2 with 1-methylpiperazine in an HBr/water solution. Both amine N atoms are protonated. The Cu—Br distances in the tetrahedral anion are in the range 2.3809 (11)–2.4131 (11) . In the crystal, moderately strong and weak intermolecular N—H...Br hydrogen bonds link the anion and cation units into an infinite two-dimensional network parallel to the ab plane.
(±)-2-Methylpiperazin-1-ium perchlorate
Cong-Hu Peng
Acta Crystallographica Section E , 2010, DOI: 10.1107/s160053681002862x
Abstract: In the title compound, C5H13N2+·ClO4 , the monoprotonated piperazine ring adopts a chair conformation. In the crystal structure, cations and anions are linked by intermolecular N—H...O and N—H...N hydrogen bonds into layers parallel to (overline{1}01).
Bis(1-methylpiperazine-1,4-diium) tetrachloridocuprate(II)
Cong-hu Peng
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811024354
Abstract: The title compound, (C5H14N2)[CuCl4], was synthesized by hydrothermal reaction of CuCl2 with 1-methylpiperazine in an HCl/water solution. Both amine N atoms are protonated. The piperazine ring adopts a chair conformation. The Cu—Cl distances in the tetrahedral anion are in the range 2.2360 (7)–2.2732 (7) . In the crystal, moderately strong and weak intermolecular N—H...Cl hydrogen bonds link the anion and cation units into an infinite two-dimensional network parallel to the ab plane.
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