WorldWideScience

Sample records for bi-directional sift predicts

  1. Bi-directional SIFT predicts a subset of activating mutations.

    Science.gov (United States)

    Lee, William; Zhang, Yan; Mukhyala, Kiran; Lazarus, Robert A; Zhang, Zemin

    2009-12-14

    Advancements in sequencing technologies have empowered recent efforts to identify polymorphisms and mutations on a global scale. The large number of variations and mutations found in these projects requires high-throughput tools to identify those that are most likely to have an impact on function. Numerous computational tools exist for predicting which mutations are likely to be functional, but none that specifically attempt to identify mutations that result in hyperactivation or gain-of-function. Here we present a modified version of the SIFT (Sorting Intolerant from Tolerant) algorithm that utilizes protein sequence alignments with homologous sequences to identify functional mutations based on evolutionary fitness. We show that this bi-directional SIFT (B-SIFT) is capable of identifying experimentally verified activating mutants from multiple datasets. B-SIFT analysis of large-scale cancer genotyping data identified potential activating mutations, some of which we have provided detailed structural evidence to support. B-SIFT could prove to be a valuable tool for efforts in protein engineering as well as in identification of functional mutations in cancer.

  2. SIFT missense predictions for genomes.

    Science.gov (United States)

    Vaser, Robert; Adusumalli, Swarnaseetha; Leng, Sim Ngak; Sikic, Mile; Ng, Pauline C

    2016-01-01

    The SIFT (sorting intolerant from tolerant) algorithm helps bridge the gap between mutations and phenotypic variations by predicting whether an amino acid substitution is deleterious. SIFT has been used in disease, mutation and genetic studies, and a protocol for its use has been previously published with Nature Protocols. This updated protocol describes SIFT 4G (SIFT for genomes), which is a faster version of SIFT that enables practical computations on reference genomes. Users can get predictions for single-nucleotide variants from their organism of interest using the SIFT 4G annotator with SIFT 4G's precomputed databases. The scope of genomic predictions is expanded, with predictions available for more than 200 organisms. Users can also run the SIFT 4G algorithm themselves. SIFT predictions can be retrieved for 6.7 million variants in 4 min once the database has been downloaded. If precomputed predictions are not available, the SIFT 4G algorithm can compute predictions at a rate of 2.6 s per protein sequence. SIFT 4G is available from http://sift-dna.org/sift4g.

  3. Performance Prediction of Differential Fibers with a Bi-Directional Optimization Approach

    Directory of Open Access Journals (Sweden)

    Yi Wang

    2013-12-01

    Full Text Available This paper develops a bi-directional prediction approach to predict the production parameters and performance of differential fibers based on neural networks and a multi-objective evolutionary algorithm. The proposed method does not require accurate description and calculation for the multiple processes, different modes and complex conditions of fiber production. The bi-directional prediction approach includes the forward prediction and backward reasoning. Particle swam optimization algorithms with K-means algorithm are used to minimize the prediction error of the forward prediction results. Based on the forward prediction, backward reasoning uses the multi-objective evolutionary algorithm to find the reasoning results. Experiments with polyester filament parameters of differential production conditions indicate that the proposed approach obtains good prediction results. The results can be used to optimize fiber production and to design differential fibers. This study also has important value and widespread application prospects regarding the spinning of differential fiber optimization.

  4. SIFT: Predicting amino acid changes that affect protein function.

    Science.gov (United States)

    Ng, Pauline C; Henikoff, Steven

    2003-07-01

    Single nucleotide polymorphism (SNP) studies and random mutagenesis projects identify amino acid substitutions in protein-coding regions. Each substitution has the potential to affect protein function. SIFT (Sorting Intolerant From Tolerant) is a program that predicts whether an amino acid substitution affects protein function so that users can prioritize substitutions for further study. We have shown that SIFT can distinguish between functionally neutral and deleterious amino acid changes in mutagenesis studies and on human polymorphisms. SIFT is available at http://blocks.fhcrc.org/sift/SIFT.html.

  5. SIFT: predicting amino acid changes that affect protein function

    OpenAIRE

    Ng, Pauline C.; Henikoff, Steven

    2003-01-01

    Single nucleotide polymorphism (SNP) studies and random mutagenesis projects identify amino acid substitutions in protein-coding regions. Each substitution has the potential to affect protein function. SIFT (Sorting Intolerant From Tolerant) is a program that predicts whether an amino acid substitution affects protein function so that users can prioritize substitutions for further study. We have shown that SIFT can distinguish between functionally neutral and deleterious amino acid changes in...

  6. Exploration of pathological prediction of chronic kidney diseases by a novel theory of bi-directional probability.

    Science.gov (United States)

    Yang, Yuan; Luo, Min; Xiao, Li; Zhu, Xue-Jing; Wang, Chang; Fu, Xiao; Yuan, Shu-Guang; Xiao, Fang; Liu, Hong; Dong, Zheng; Liu, Fu-You; Sun, Lin

    2016-08-25

    In the clinic, the pathological types of chronic kidney diseases (CKD) are considered references for choosing treatment protocols. From a statistical viewpoint, a non-invasive method to predict pathological types of CKD is a focus of our work. In the current study, following a frequency analysis of the clinical indices of 588 CKD patients in the department of nephrology, a third-grade class-A hospital, a novel theory is proposed: "bi-directional cumulative probability dichotomy". Further, two models for the prediction and differential diagnosis of CKD pathological type are established. The former indicates an occurrence probability of the pathological types, and the latter indicates an occurrence of CKD pathological type according to logistic binary regression. To verify the models, data were collected from 135 patients, and the results showed that the highest accuracy rate on membranous nephropathy (MN-100%), followed by IgA nephropathy (IgAN-83.33%) and mild lesion type (MLN-73.53%), whereas lower prediction accuracy was observed for mesangial proliferative glomerulonephritis (0%) and focal segmental sclerosis type (21.74%). The models of bi-directional probability prediction and differential diagnosis indicate a good prediction value in MN, IgAN and MLN and may be considered alternative methods for the pathological discrimination of CKD patients who are unable to undergo renal biopsy.

  7. SIFT web server: predicting effects of amino acid substitutions on proteins.

    Science.gov (United States)

    Sim, Ngak-Leng; Kumar, Prateek; Hu, Jing; Henikoff, Steven; Schneider, Georg; Ng, Pauline C

    2012-07-01

    The Sorting Intolerant from Tolerant (SIFT) algorithm predicts the effect of coding variants on protein function. It was first introduced in 2001, with a corresponding website that provides users with predictions on their variants. Since its release, SIFT has become one of the standard tools for characterizing missense variation. We have updated SIFT's genome-wide prediction tool since our last publication in 2009, and added new features to the insertion/deletion (indel) tool. We also show accuracy metrics on independent data sets. The original developers have hosted the SIFT web server at FHCRC, JCVI and the web server is currently located at BII. The URL is http://sift-dna.org (24 May 2012, date last accessed).

  8. Predicting the effects of coding non-synonymous variants on protein function using the SIFT algorithm.

    Science.gov (United States)

    Kumar, Prateek; Henikoff, Steven; Ng, Pauline C

    2009-01-01

    The effect of genetic mutation on phenotype is of significant interest in genetics. The type of genetic mutation that causes a single amino acid substitution (AAS) in a protein sequence is called a non-synonymous single nucleotide polymorphism (nsSNP). An nsSNP could potentially affect the function of the protein, subsequently altering the carrier's phenotype. This protocol describes the use of the 'Sorting Tolerant From Intolerant' (SIFT) algorithm in predicting whether an AAS affects protein function. To assess the effect of a substitution, SIFT assumes that important positions in a protein sequence have been conserved throughout evolution and therefore substitutions at these positions may affect protein function. Thus, by using sequence homology, SIFT predicts the effects of all possible substitutions at each position in the protein sequence. The protocol typically takes 5-20 min, depending on the input. SIFT is available as an online tool (http://sift.jcvi.org).

  9. The Bi-Directional Prediction of Carbon Fiber Production Using a Combination of Improved Particle Swarm Optimization and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Chuncai Xiao

    2014-12-01

    Full Text Available This paper creates a bi-directional prediction model to predict the performance of carbon fiber and the productive parameters based on a support vector machine (SVM and improved particle swarm optimization (IPSO algorithm (SVM-IPSO. In the SVM, it is crucial to select the parameters that have an important impact on the performance of prediction. The IPSO is proposed to optimize them, and then the SVM-IPSO model is applied to the bi-directional prediction of carbon fiber production. The predictive accuracy of SVM is mainly dependent on its parameters, and IPSO is thus exploited to seek the optimal parameters for SVM in order to improve its prediction capability. Inspired by a cell communication mechanism, we propose IPSO by incorporating information of the global best solution into the search strategy to improve exploitation, and we employ IPSO to establish the bi-directional prediction model: in the direction of the forward prediction, we consider productive parameters as input and property indexes as output; in the direction of the backward prediction, we consider property indexes as input and productive parameters as output, and in this case, the model becomes a scheme design for novel style carbon fibers. The results from a set of the experimental data show that the proposed model can outperform the radial basis function neural network (RNN, the basic particle swarm optimization (PSO method and the hybrid approach of genetic algorithm and improved particle swarm optimization (GA-IPSO method in most of the experiments. In other words, simulation results demonstrate the effectiveness and advantages of the SVM-IPSO model in dealing with the problem of forecasting.

  10. SIFT Indel: predictions for the functional effects of amino acid insertions/deletions in proteins.

    Science.gov (United States)

    Hu, Jing; Ng, Pauline C

    2013-01-01

    Indels in the coding regions of a gene can either cause frameshifts or amino acid insertions/deletions. Frameshifting indels are indels that have a length that is not divisible by 3 and subsequently cause frameshifts. Indels that have a length divisible by 3 cause amino acid insertions/deletions or block substitutions; we call these 3n indels. The new amino acid changes resulting from 3n indels could potentially affect protein function. Therefore, we construct a SIFT Indel prediction algorithm for 3n indels which achieves 82% accuracy, 81% sensitivity, 82% specificity, 82% precision, 0.63 MCC, and 0.87 AUC by 10-fold cross-validation. We have previously published a prediction algorithm for frameshifting indels. The rules for the prediction of 3n indels are different from the rules for the prediction of frameshifting indels and reflect the biological differences of these two different types of variations. SIFT Indel was applied to human 3n indels from the 1000 Genomes Project and the Exome Sequencing Project. We found that common variants are less likely to be deleterious than rare variants. The SIFT indel prediction algorithm for 3n indels is available at http://sift-dna.org/

  11. Bi-directional block is superior to non-inducibility in predicting freedom from atrial fibrillation after pulmonary vein isolation

    Directory of Open Access Journals (Sweden)

    Sherif H. Zaky

    2011-03-01

    Conclusion: Achieving BD block improves results and may predict maintenance of sinus rhythm more than NI of AF after PVI. It can be used as an electrophysiological endpoint alternative to or in conjunction with non inducibility in AF ablation procedures.

  12. Bi-directional homogenization equivalent modeling for the prediction of thermo-mechanical properties of a multi-layered printed circuit board (PCB)

    Science.gov (United States)

    Joo, Sung-Jun; Park, Buhm; Kim, Do-Hyoung; Kwak, Dong-Ok; Park, Junhong; Kim, Hak-Sung

    2016-04-01

    Warpage of multi-layered printed circuit boards (PCB) during the reflow process is a serious problem which affects the reliability of solder ball connections between the PCB and the mounted semi-conductor packages in electronic devices. It is essential to predict the warpage of the PCB accurately; however, the complicated copper patterns in multi-layered PCBs render a full modeling analysis impossible due to the excessive computing time required. To overcome this problem, we have developed analytical equations of three Cu patterns (line, square, and grid) for the application of thermo-mechanical properties simply by equivalent modeling of Cu patterns. In the proposed equations, the effect of thermo-viscoelastic properties as well as the influence of surrounding layers such as woven glass fabric/BT (bismaleimide triazine), composite laminate (BT core), and photoimageable solder resist (PSR) were considered. To verify the developed equations, vibration tests based on the wave propagation approach were performed at various temperatures. Good agreement was observed between the equivalent model and the experimental results.

  13. The SIFT Code Specification

    Science.gov (United States)

    1983-01-01

    The specification of Software Implemented Fault Tolerance (SIFT) consists of two parts, the specifications of the SIFT models and the specifications of the SIFT PASCAL program which actually implements the SIFT system. The code specifications are the last of a hierarchy of models describing the operation of the SIFT system and are related to the SIFT models as well as the PASCAL program. These Specifications serve to link the SIFT models to the running program. The specifications are very large and detailed and closely follow the form and organization of the PASCAL code. In addition to describing each of the components of the SIFT code, the code specifications describe the assumptions of the upper SIFT models which are required to actually prove that the code will work as specified. These constraints are imposed primarily on the schedule tables.

  14. Behavior of composite rigid frame bridge under bi-directional seismic excitations

    Directory of Open Access Journals (Sweden)

    Xiaogang Liu

    2014-02-01

    Full Text Available Pushover analysis and time history analysis are conducted to explore the bi-directional seismic behavior of composite steel-concrete rigid frame bridge, which is composed of RC piers and steel-concrete composite girders. Both longitudinal and transverse directions excitations are investigated using OpenSees. Firstly, the applicability of pushover analysis based on the fundamental mode is discussed. Secondly, an improved pushover analysis method considering the contribution of higher modes is proposed, and the applicability on composite rigid frame bridges under bi-directional earthquake is verified. Based on this method, an approach to predict the displacement responses of composite rigid frame bridge under random bi-directional seismic excitations by revising the elasto-plastic demand curve is also proposed. It is observed that the developed method yield a good estimate on the responses of composite rigid frame bridges under bi-directional seismic excitations.

  15. Detection algorithm of moving object based on predicted SIFT feature%基于SIFT特征与预测的运动目标检测算法

    Institute of Scientific and Technical Information of China (English)

    吴忠良; 余升

    2015-01-01

    An improved detection algorithm of SIFT feature marching is provided for rapid detection to moving object in dy⁃namic scene. The matched feature points are extracted by SIFT method,and the rotation parameter model is established for global motion. The influence of exterior points is eliminated by RANSAC method. The global motion parameters are solved by the least square method,and the feature points are updated by the updating strategy based on residual image block. This matching algo⁃rithm is based on the predicted SIFT feature points,which can remain the high performance of SIFT method and improve the de⁃tection rate of the object. Compared with the experimental results of block matching algorithm,it demonstrates that this algo⁃rithm can detect moving object accurately and in real⁃time.%为了在动态场景下对运动目标进行快速检测,提出一个改进的SIFT特征匹配的检测算法。首先采用SIFT方法提取匹配的特征点;然后为全局运动建立起旋转参数模型,并使用RANSAC方法排除外点的影响,运用最小二乘法求解全局运动参数;最后利用基于残差图像块的更新策略对特征点进行更新。该算法是基于预测的SIFT特征点匹配算法,不仅保持了SIFT方法的优越性能,而且提高了检测目标的速度。与块匹配算法的实验结果对比表明,该算法可以实时准确地检测出运动目标。

  16. Silent and Efficient Supersonic Bi-Directional Flying Wing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a Phase I study for a novel concept of a supersonic bi-directional (SBiDir) flying wing (FW) that has the potential to revolutionize supersonic flight...

  17. Global evaluation of ammonia bi-directional exchange

    OpenAIRE

    Zhu, L; D. Henze; J. Bash; G.-R. Jeong; Cady-Pereira, K.; Shephard, M; Luo, M; F. Paulot; Capps, S.

    2015-01-01

    Bi-directional air–surface exchange of ammonia (NH3) has been neglected in many air quality models. In this study, we implement the bi-directional exchange of NH3 in the GEOS-Chem global chemical transport model. We also introduce an updated diurnal variability scheme for NH3 livestock emissions and evaluate the recently developed MASAGE_NH3 bottom up inventory. While updated diurnal variability improves comparison of modeled-to-hourly in situ measurements i...

  18. Design verification of SIFT

    Science.gov (United States)

    Moser, Louise; Melliar-Smith, Michael; Schwartz, Richard

    1987-01-01

    A SIFT reliable aircraft control computer system, designed to meet the ultrahigh reliability required for safety critical flight control applications by use of processor replications and voting, was constructed for SRI, and delivered to NASA Langley for evaluation in the AIRLAB. To increase confidence in the reliability projections for SIFT, produced by a Markov reliability model, SRI constructed a formal specification, defining the meaning of reliability in the context of flight control. A further series of specifications defined, in increasing detail, the design of SIFT down to pre- and post-conditions on Pascal code procedures. Mechanically checked mathematical proofs were constructed to demonstrate that the more detailed design specifications for SIFT do indeed imply the formal reliability requirement. An additional specification defined some of the assumptions made about SIFT by the Markov model, and further proofs were constructed to show that these assumptions, as expressed by that specification, did indeed follow from the more detailed design specifications for SIFT. This report provides an outline of the methodology used for this hierarchical specification and proof, and describes the various specifications and proofs performed.

  19. Global evaluation of ammonia bi-directional exchange

    Directory of Open Access Journals (Sweden)

    L. Zhu

    2015-02-01

    Full Text Available Bi-directional air–surface exchange of ammonia (NH3 has been neglected in many air quality models. In this study, we implement the bi-directional exchange of NH3 in the GEOS-Chem global chemical transport model. We also introduce an updated diurnal variability scheme for NH3 livestock emissions and evaluate the recently developed MASAGE_NH3 bottom up inventory. While updated diurnal variability improves comparison of modeled-to-hourly in situ measurements in the Southeastern US, NH3 concentrations decrease throughout the globe, up to 17 ppb in India and Southeastern China, with corresponding decreases in aerosol nitrate by up to 7 μg m−3. The ammonium (NH4+ soil pool in the bi-directional exchange model largely extends the NH3 lifetime in the atmosphere. Including bi-directional exchange generally increases NH3 gross emissions (7.1% and surface concentrations (up to 3.9 ppb throughout the globe in July, except in India and Southeastern China. In April and October, it decreases NH3 gross emissions in the Northern Hemisphere (e.g., 43.6% in April in China and increases NH3 gross emissions in the Southern Hemisphere. Bi-directional exchange does not largely impact NH4+ wet deposition overall. While bi-directional exchange is fundamentally a better representation of NH3 emissions from fertilizers, emissions from primary sources are still underestimated and thus significant model biases remain when compared to in situ measurements in the US. The adjoint of bi-directional exchange has also been developed for the GEOS-Chem model and is used to investigate the sensitivity of NH3 concentrations with respect to soil pH and fertilizer application rate. This study thus lays the groundwork for future inverse modeling studies to more directly constrain these physical processes rather than tuning bulk uni-directional NH3 emissions.

  20. Global evaluation of ammonia bi-directional exchange

    Science.gov (United States)

    Zhu, L.; Henze, D.; Bash, J.; Jeong, G.-R.; Cady-Pereira, K.; Shephard, M.; Luo, M.; Paulot, F.; Capps, S.

    2015-02-01

    Bi-directional air-surface exchange of ammonia (NH3) has been neglected in many air quality models. In this study, we implement the bi-directional exchange of NH3 in the GEOS-Chem global chemical transport model. We also introduce an updated diurnal variability scheme for NH3 livestock emissions and evaluate the recently developed MASAGE_NH3 bottom up inventory. While updated diurnal variability improves comparison of modeled-to-hourly in situ measurements in the Southeastern US, NH3 concentrations decrease throughout the globe, up to 17 ppb in India and Southeastern China, with corresponding decreases in aerosol nitrate by up to 7 μg m-3. The ammonium (NH4+) soil pool in the bi-directional exchange model largely extends the NH3 lifetime in the atmosphere. Including bi-directional exchange generally increases NH3 gross emissions (7.1%) and surface concentrations (up to 3.9 ppb) throughout the globe in July, except in India and Southeastern China. In April and October, it decreases NH3 gross emissions in the Northern Hemisphere (e.g., 43.6% in April in China) and increases NH3 gross emissions in the Southern Hemisphere. Bi-directional exchange does not largely impact NH4+ wet deposition overall. While bi-directional exchange is fundamentally a better representation of NH3 emissions from fertilizers, emissions from primary sources are still underestimated and thus significant model biases remain when compared to in situ measurements in the US. The adjoint of bi-directional exchange has also been developed for the GEOS-Chem model and is used to investigate the sensitivity of NH3 concentrations with respect to soil pH and fertilizer application rate. This study thus lays the groundwork for future inverse modeling studies to more directly constrain these physical processes rather than tuning bulk uni-directional NH3 emissions.

  1. Piezoelectric power converter with bi-directional power transfer

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a bi-directional piezoelectric power converter com¬ prising a piezoelectric transformer. The piezoelectric transformer comprises an input electrode electrically coupled to a primary section of the piezoelectric transformer and an output electrode electrically...... coupled to an output section of the piezoelectric transformer to provide a transformer output signal. A bi-directional switching circuit is coupled between the output electrode and a DC or AC output voltage of the power converter. Forward and reverse current conducting periods of the bi......, a reverse current is conducted through the bi-directional switching circuit from the DC or AC output voltage to the output electrode to discharge the DC or AC output voltage and return power to the primary section of the piezoelectric transformer....

  2. Use of a least absolute shrinkage and selection operator (LASSO) model to selected ion flow tube mass spectrometry (SIFT-MS) analysis of exhaled breath to predict the efficacy of dialysis: a pilot study.

    Science.gov (United States)

    Wang, Maggie Haitian; Chong, Ka Chun; Storer, Malina; Pickering, John W; Endre, Zoltan H; Lau, Steven Yf; Kwok, Chloe; Lai, Maria; Chung, Hau Yin; Ying Zee, Benny Chung

    2016-09-28

    Selected ion flow tube-mass spectrometry (SIFT-MS) provides rapid, non-invasive measurements of a full-mass scan of volatile compounds in exhaled breath. Although various studies have suggested that breath metabolites may be indicators of human disease status, many of these studies have included few breath samples and large numbers of compounds, limiting their power to detect significant metabolites. This study employed a least absolute shrinkage and selective operator (LASSO) approach to SIFT-MS data of breath samples to preliminarily evaluate the ability of exhaled breath findings to monitor the efficacy of dialysis in hemodialysis patients. A process of model building and validation showed that blood creatinine and urea concentrations could be accurately predicted by LASSO-selected masses. Using various precursors, the LASSO models were able to predict creatinine and urea concentrations with high adjusted R-square (>80%) values. The correlation between actual concentrations and concentrations predicted by the LASSO model (using precursor H3O(+)) was high (Pearson correlation coefficient  =  0.96). Moreover, use of full mass scan data provided a better prediction than compounds from selected ion mode. These findings warrant further investigations in larger patient cohorts. By employing a more powerful statistical approach to predict disease outcomes, breath analysis using SIFT-MS technology could be applicable in future to daily medical diagnoses.

  3. High Efficiency Bi-Directional Converter Used For Renewable System

    Directory of Open Access Journals (Sweden)

    M. Desal Raja

    2014-02-01

    Full Text Available This paper presents an Isolated bi-directional converter for renewable system. Voltage stress and current stress was decreses in switches. Power flows in both side. The proposed converter three phase ac voltage to dc voltage, dc voltage to three phase a.c voltage and synchronous the two voltage source. Silicon carbide diodes and bi-directional switches Mosfet’s are used for decreases the switching loss. LC Series resonant converter connected to the high efficiency. This converter power conversion control by the output voltage information.

  4. SIFT applied to CBIR

    Directory of Open Access Journals (Sweden)

    ALMEIDA, J.

    2009-12-01

    Full Text Available Content-Based Image Retrieval (CBIR is a challenging task. Common approaches use only low-level features. Notwithstanding, such CBIR solutions fail on capturing some local features representing the details and nuances of scenes. Many techniques in image processing and computer vision can capture these scene semantics. Among them, the Scale Invariant Features Transform~(SIFT has been widely used in a lot of applications. This approach relies on the choice of several parameters which directly impact its effectiveness when applied to retrieve images. In this paper, we discuss the results obtained in several experiments proposed to evaluate the application of the SIFT in CBIR tasks.

  5. A bi-directional leading-edge vortex in slow-flying bats

    Science.gov (United States)

    Wang, Shizhao; Zhang, Xin; He, Guowei

    2011-11-01

    A leading-edge vortex (LEV) is crucial to bat afloat, since a LEV could generate high lift which could not be predicted by the conventional aerodynamics theories. The LEV usually exhibits an intensive spiral vortex of a unidirectional axial flow on the top surface of wing. In this study, we numerically simulate a slowing-flying bat using immersed boundary method. The morphology and kinematics of bat are taken from experimental measurements. It is observed from our simulation that the stretching and collapse motions of wing could induce a bi-directional axial flow. The bi-directional axial flows stabilize the LEV and enhance its intensity. The observation is further investigated by using a simple model: the flows around a spanwise oscillating plate. The spanwise oscillation could enhance the LEV and make its more stable. This result implies a link of bat kinematics with its unusual aerodynamic performances.

  6. Learning to Monitor Machine Health with Convolutional Bi-Directional LSTM Networks

    Directory of Open Access Journals (Sweden)

    Rui Zhao

    2017-01-01

    Full Text Available In modern manufacturing systems and industries, more and more research efforts have been made in developing effective machine health monitoring systems. Among various machine health monitoring approaches, data-driven methods are gaining in popularity due to the development of advanced sensing and data analytic techniques. However, considering the noise, varying length and irregular sampling behind sensory data, this kind of sequential data cannot be fed into classification and regression models directly. Therefore, previous work focuses on feature extraction/fusion methods requiring expensive human labor and high quality expert knowledge. With the development of deep learning methods in the last few years, which redefine representation learning from raw data, a deep neural network structure named Convolutional Bi-directional Long Short-Term Memory networks (CBLSTM has been designed here to address raw sensory data. CBLSTM firstly uses CNN to extract local features that are robust and informative from the sequential input. Then, bi-directional LSTM is introduced to encode temporal information. Long Short-Term Memory networks(LSTMs are able to capture long-term dependencies and model sequential data, and the bi-directional structure enables the capture of past and future contexts. Stacked, fully-connected layers and the linear regression layer are built on top of bi-directional LSTMs to predict the target value. Here, a real-life tool wear test is introduced, and our proposed CBLSTM is able to predict the actual tool wear based on raw sensory data. The experimental results have shown that our model is able to outperform several state-of-the-art baseline methods.

  7. Bi-directional Secure Communication Based on Discrete Chaotic Synchronization

    Institute of Scientific and Technical Information of China (English)

    LONG Min; QIU Shui-Sheng; PENG Fei

    2007-01-01

    Discrete chaotic systems are used for bi-directional secure communication. Both sides of communication keep sending signals to achieve their synchronization, and then recover the messages. However, the third side without keys cannot get useful information. Known-plaintext attack is also engaged to analyze this method, and the simulation results show that the proposed method can reach high security performance.

  8. Transfer of Pragmatic Competences: A Bi-Directional Perspective

    Science.gov (United States)

    Su, I-Ru

    2010-01-01

    This study investigated the bi-directionality of language transfer (first language [L1] to second language [L2] and L2 to L1) at the pragmatic level with a focus on the speech act of request. The L2 participants were Chinese English as a foreign language (EFL) learners at the intermediate and advanced levels. Data were collected via discourse…

  9. High Voltage Bi-directional Flyback Converter for Capacitive Actuator

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    This paper presents a high voltage DC-DC converter topology for bi-directional energy transfer between a low voltage DC source and a high voltage capacitive load. The topology is a bi-directional flyback converter with variable switching frequency control during the charge mode, and constant...... switching frequency control during the discharge mode. The converter is capable of charging the capacitive load from 24 V DC source to 2.5 kV, and discharges it to 0 V. The flyback converter has been analyzed in detail during both charge and discharge modes, by considering all the parasitic elements...... in the converter, including the most dominating parameters of the high voltage transformer viz., self-capacitance and leakage inductance. The specific capacitive load for this converter is a dielectric electro active polymer (DEAP) actuator, which can be used as an effective replacement for conventional actuators...

  10. Bi-directional associations between psychological arousal, cortisol, and sleep

    DEFF Research Database (Denmark)

    Garde, Anne Helene; Albertsen, Karen; Persson, Roger

    2012-01-01

    The aim was to elucidate the possible bi-directional relation between daytime psychological arousal, cortisol, and self-reported sleep in a group of healthy employees in active employment. Logbook ratings of sleep (Karolinska Sleep Questionnaire), stress, and energy, as well as positive and negat......The aim was to elucidate the possible bi-directional relation between daytime psychological arousal, cortisol, and self-reported sleep in a group of healthy employees in active employment. Logbook ratings of sleep (Karolinska Sleep Questionnaire), stress, and energy, as well as positive...... and problems during the day. The results underpin the possibility that arousal and poor sleep might create a self-reinforcing vicious circle that negatively affects a person's well-being....

  11. Bi-directional normalized difference vegetation index: concept and application

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The data products of land surface bi-directional reflectance distribution function (BRDF) from the space-borne Polarization and Directionality of the Earth Reflectance (POLDER) of France and the Moderate Resolution Imaging Spectroradiometer (MODIS)of USA are available recently, but the atmospheric correction for meeting the requirement of quantitative remote sensing is still a very dfficult problem. This paper presents a concept: bi-directional normalized difference vegetation index (Bi-NDVI), in order to consider simul taneously the effects of both land surface BRDF and atmospheric path scattering. An atmospheric quality index is thus defined for satellite multi-angular observations. The quality of MODIS/BRDF data products can be improved notably through iterative inversion weighed by this index.

  12. Bi-directional interhemispheric inhibition during unimanual sustained contractions

    Directory of Open Access Journals (Sweden)

    Ni Zhen

    2009-04-01

    Full Text Available Abstract Background The interaction between homologous muscle representations in the right and left primary motor cortex was studied using a paired-pulse transcranial magnetic stimulation (TMS protocol known to evoke interhemispheric inhibition (IHI. The timecourse and magnitude of IHI was studied in fifteen healthy right-handed adults at several interstimulus intervals between the conditioning stimulus and test stimulus (6, 8, 10, 12, 30, 40, 50 ms. IHI was studied in the motor dominant to non-dominant direction and vice versa while the right or left hand was at rest, performing isometric contraction of the first dorsal interosseous (FDI muscle, and isometric contraction of the FDI muscle in the context of holding a pen. Results Compared with rest, IHI was reduced at all ISIs during contraction of either type (with or without the context of pen. IHI was reduced bi-directionally without evidence of hemispheric dominance. Further, contraction of the hand contralateral to the conditioning and test pulse yielded similar reductions in IHI. Conclusion These data provide evidence for bi-directional reduction of IHI during unimanual contractions. During unimanual, sustained contractions of the hand, the contralateral and ipsilateral motor cortices demonstrate reduced inhibition. The data suggest that unimanual movement decreases inhibition bi-directionally across motor hemispheres and offer one explanation for the observation of ipsilateral M1 activity during hand movements.

  13. High-Speed Optical Local Access Network System Using Bi-Directional Polarization Multiplexing

    Institute of Scientific and Technical Information of China (English)

    Mitsuru Miyauchi; Yanjun Sun

    2003-01-01

    A high-speed and economical optical local access network system is proposed where bi-directional polarization multiplexing is applied to a bi-directional transmission. Experimental results using a prototype system confirmlow optical loss and environmental stabilities.

  14. High-Speed Optical Local Access Network System Using Bi-Directional Polarization Multiplexing

    Institute of Scientific and Technical Information of China (English)

    Mitsuru; Miyauchi; Yanjun; Sun

    2003-01-01

    A high-speed and economical optical local access network system is proposed where bi-directional polarization multiplexing is applied to a bi-directional transmission. Experimental results using a prototype system confirm low optical loss and environmental stabilities.

  15. Bi-directional thruster development and test report

    Science.gov (United States)

    Jacot, A. D.; Bushnell, G. S.; Anderson, T. M.

    1990-01-01

    The design, calibration and testing of a cold gas, bi-directional throttlable thruster are discussed. The thruster consists of an electro-pneumatic servovalve exhausting through opposite nozzles with a high gain pressure feedback loop to optimize performance. The thruster force was measured to determine hysteresis and linearity. Integral gain was used to maximize performance for linearity, hysteresis, and minimum thrust requirements. Proportional gain provided high dynamic response (bandwidth and phase lag). Thruster performance is very important since the thrusters are intended to be used for active control.

  16. Bi-Directional DC-DC Converter for PHEV Applications

    Energy Technology Data Exchange (ETDEWEB)

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  17. OBJECT RECOGNITION WITH SIFT AND MI-SIFT METHODS

    OpenAIRE

    HARDALAÇ, Fırat; ORMAN, Abdullah; URAL, Berkan; Eren, Ali

    2015-01-01

    This study, which has been commonly used in object recognition area for 10 years, is based on the recognition of special point-based objects and there are differences in some areas such as luminance, anguler and resistance from cyclic and dimensional changes. Generally, scalar invariant feature transformation (scale invariant feature transform- SIFT) method and independent feature transformation (mirror reflection invariant feature- MIFT) method which is a weak point of SIFT method, also is c...

  18. Moral judgment modulation by disgust is bi-directionally moderated by individual sensitivity

    Directory of Open Access Journals (Sweden)

    How Hwee eOng

    2014-03-01

    Full Text Available Modern theories of moral judgment predict that both conscious reasoning and unconscious emotional influences affect the way people decide about right and wrong. In a series of experiments, we tested the effect of subliminal and conscious priming of disgust facial expressions on moral dilemmas. Trolley-car-type scenarios were used, with subjects rating how acceptable they found the utilitarian course of action to be. On average, subliminal priming of disgust facial expressions resulted in higher rates of utilitarian judgments compared to neutral facial expressions. Further, in replication, we found that individual change in moral acceptability ratings due to disgust priming was modulated by individual sensitivity to disgust, revealing a bi-directional function. Our second replication extended this result to show that the function held for both subliminally and consciously presented stimuli. Combined across these experiments, we show a reliable bi-directional function, with presentation of disgust expression primes to individuals with higher disgust sensitivity resulting in more utilitarian judgments (i.e., number-based and presentations to individuals with lower sensitivity resulting in more deontological judgments (i.e., rules-based. Our results may reconcile previous conflicting reports of disgust modulation of moral judgment by modeling how individual sensitivity to disgust determines the direction and degree of this effect.

  19. Bi-directional electrical characterisation of microbial fuel cell.

    Science.gov (United States)

    Degrenne, N; Ledezma, P; Bevilacqua, P; Buret, F; Allard, B; Greenman, J; Ieropoulos, I A

    2013-01-01

    The electrical performance of microbial fuel cells in steady-state is usually investigated by standard characterisation methods that reveal many important parameters e.g. maximum power. This paper introduces a novel "bi-directional" method to study how the acquisition parameters (i.e. sweep rate and sweep regime) can influence measurements and consequently performance estimations. The investigation exhibited considerable differences (hysteresis) between the forward and backward characterisation regimes, indicating a difficulty to reach steady-state under certain conditions. Moreover, it is found that fast sweep rates (time-step of 2 min) can lead to an overestimation of the short-circuit currents, while prolonged operation with high external loads leads to maximum power overestimation and extended conditioning at high currents can result in its underestimation.

  20. Bi-directional evolutionary optimization for photonic band gap structures

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Fei [Centre for Innovative Structures and Materials, School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476, Melbourne, VIC 3001 (Australia); School of Civil Engineering, Central South University, Changsha 410075 (China); Huang, Xiaodong, E-mail: huang.xiaodong@rmit.edu.au [Centre for Innovative Structures and Materials, School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476, Melbourne, VIC 3001 (Australia); Key Laboratory of Advanced Technology for Vehicle Body Design & Manufacture, Hunan University, Changsha, 410082 (China); Jia, Baohua [Centre for Micro-Photonics, Faculty of Engineering & Industrial Science, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122 (Australia)

    2015-12-01

    Toward an efficient and easy-implement optimization for photonic band gap structures, this paper extends the bi-directional evolutionary structural optimization (BESO) method for maximizing photonic band gaps. Photonic crystals are assumed to be periodically composed of two dielectric materials with the different permittivity. Based on the finite element analysis and sensitivity analysis, BESO starts from a simple initial design without any band gap and gradually re-distributes dielectric materials within the unit cell so that the resulting photonic crystal possesses a maximum band gap between two specified adjacent bands. Numerical examples demonstrated the proposed optimization algorithm can successfully obtain the band gaps from the first to the tenth band for both transverse magnetic and electric polarizations. Some optimized photonic crystals exhibit novel patterns markedly different from traditional designs of photonic crystals.

  1. Sandwiched structural panel having a bi-directional core structure

    Science.gov (United States)

    Weddendorf, Bruce (Inventor)

    1995-01-01

    A structural panel assembly has a bi-directional core structure sandwiched between and secured to a pair of outer side wall members. The core structure is formed from first and second perpendicular series of elongated strip members having crenelated configurations. The strip members in the first series thereof are transversely interwoven with the strip members in the second series thereof in a manner such that crest portions of the strip members in the first series overlie and oppose trough portions of the strip members in the second series, and trough portions of the strip members in the first series underlie and oppose crest portions of the strip members in the second series. The crest portions of all of the strip members lie generally in a first plane and are secured to the inner side of one of the panel assembly outer side walls, and the trough portions of all of the strip members lie generally in a second plane and are secured to the inner side of the other panel assembly outer side wall.

  2. Design of Bi-Directional Hydrofoils for Tidal Current Turbines

    Science.gov (United States)

    Nedyalkov, Ivaylo; Wosnik, Martin

    2015-11-01

    Tidal Current Turbines operate in flows which reverse direction. Bi-directional hydrofoils have rotational symmetry and allow such turbines to operate without the need for pitch or yaw control, decreasing the initial and maintenance costs. A numerical test-bed was developed to automate the simulations of hydrofoils in OpenFOAM and was utilized to simulate the flow over eleven classes of hydrofoils comprising a total of 700 foil shapes at different angles of attack. For promising candidate foil shapes physical models of 75 mm chord and 150 mm span were fabricated and tested in the University of New Hampshire High-Speed Cavitation Tunnel (HiCaT). The experimental results were compared to the simulations for model validation. The numerical test-bed successfully generated simulations for a wide range of foil shapes, although, as expected, the k - ω - SST turbulence model employed here was not adequate for some of the foils and for large angles of attack at which separation occurred. An optimization algorithm is currently being coupled with the numerical test-bed and additional turbulence models will be implemented in the future.

  3. SIFT flow: dense correspondence across scenes and its applications.

    Science.gov (United States)

    Liu, Ce; Yuen, Jenny; Torralba, Antonio

    2011-05-01

    While image alignment has been studied in different areas of computer vision for decades, aligning images depicting different scenes remains a challenging problem. Analogous to optical flow, where an image is aligned to its temporally adjacent frame, we propose SIFT flow, a method to align an image to its nearest neighbors in a large image corpus containing a variety of scenes. The SIFT flow algorithm consists of matching densely sampled, pixelwise SIFT features between two images while preserving spatial discontinuities. The SIFT features allow robust matching across different scene/object appearances, whereas the discontinuity-preserving spatial model allows matching of objects located at different parts of the scene. Experiments show that the proposed approach robustly aligns complex scene pairs containing significant spatial differences. Based on SIFT flow, we propose an alignment-based large database framework for image analysis and synthesis, where image information is transferred from the nearest neighbors to a query image according to the dense scene correspondence. This framework is demonstrated through concrete applications such as motion field prediction from a single image, motion synthesis via object transfer, satellite image registration, and face recognition.

  4. Monitoring and queuing for sift

    Science.gov (United States)

    Wilson, L.

    1983-01-01

    The SIFT instrumentation is called the "Window." This window was designed to collect internal data from SIFT while having minimal overhead. Window consists of Sender and Relay components. Sender is to be run on processors 0..5 and Relay will run on processor 6. Sender will gather values (currently 12) during the subframe allocated to a task and broadcast these values at the start of the next subframe. This timing was selected to guarantee Relay 3.2ms to collect and transmit the data.

  5. Clinico-serologic co-relation in bi-directional ABO incompatible hemopoietic stem cell transplantation

    Directory of Open Access Journals (Sweden)

    Sabita Basu

    2015-01-01

    Full Text Available Background: The ABO blood group system is of prime significance in red cell transfusion and organ transplantation. However, ABO compatibility is not critical in allogenic hemopoietic stem cell transplantation (HSCT and approximately 40-50% of hemopoietic stem cell transplants are ABO incompatible. This incompatibility may be major, minor or bi-directional. Though there are descriptions of transfusion practice and protocols in ABO incompatible HSCT, there are considerable variations and transfusion support in these patients can be very challenging. Aims: The immunohematologic observations in two cases of bi-directional ABO incompatible HSCT have been described, and clinico-serologic correlation has been attempted. Materials and Methods: In both cases, peripheral blood stem cell harvests were obtained using the Cobe spectra cell separator. Immunohematologic assessments in the donor and recipient were done as a part of pre HSCT evaluation. Both the standard tube technique and column agglutination method (Ortho Biovue Micro Bead System was used. Antibody screen was done by column agglutination method using three cell panel (Surgiscreen cells. Isoagglutinin titration was done by the master dilution method and standard validated techniques were used. Results: The pattern of laboratory findings in the two cases was different and so were the clinical outcomes. Although there was early engraftment in the first case, the second case developed pure red cell aplasia and this was well-reflected in the immunohematologic assessments. Conclusion: Immunohematologic assessment correlated well with the clinical picture and could be used to predict clinical outcome and onset of complications in ABO incompatible HSCT.

  6. A chronic generalized bi-directional brain-machine interface

    Science.gov (United States)

    Rouse, A. G.; Stanslaski, S. R.; Cong, P.; Jensen, R. M.; Afshar, P.; Ullestad, D.; Gupta, R.; Molnar, G. F.; Moran, D. W.; Denison, T. J.

    2011-06-01

    A bi-directional neural interface (NI) system was designed and prototyped by incorporating a novel neural recording and processing subsystem into a commercial neural stimulator architecture. The NI system prototype leverages the system infrastructure from an existing neurostimulator to ensure reliable operation in a chronic implantation environment. In addition to providing predicate therapy capabilities, the device adds key elements to facilitate chronic research, such as four channels of electrocortigram/local field potential amplification and spectral analysis, a three-axis accelerometer, algorithm processing, event-based data logging, and wireless telemetry for data uploads and algorithm/configuration updates. The custom-integrated micropower sensor and interface circuits facilitate extended operation in a power-limited device. The prototype underwent significant verification testing to ensure reliability, and meets the requirements for a class CF instrument per IEC-60601 protocols. The ability of the device system to process and aid in classifying brain states was preclinically validated using an in vivo non-human primate model for brain control of a computer cursor (i.e. brain-machine interface or BMI). The primate BMI model was chosen for its ability to quantitatively measure signal decoding performance from brain activity that is similar in both amplitude and spectral content to other biomarkers used to detect disease states (e.g. Parkinson's disease). A key goal of this research prototype is to help broaden the clinical scope and acceptance of NI techniques, particularly real-time brain state detection. These techniques have the potential to be generalized beyond motor prosthesis, and are being explored for unmet needs in other neurological conditions such as movement disorders, stroke and epilepsy.

  7. Bi-directional Multi Dimension CAP Transmission for Smart Grid Communication Services

    DEFF Research Database (Denmark)

    Zhang, Xu; Binti Othman, Maisara; Pang, Xiaodan

    2012-01-01

    We experimentally demonstrate bi-directional multi dimension carrierless amplitude and phase (CAP) transmission for smart grid communication services based on optical fiber networks. The proposed system is able to support multi-Gb/s transmission with high spectral efficiency.......We experimentally demonstrate bi-directional multi dimension carrierless amplitude and phase (CAP) transmission for smart grid communication services based on optical fiber networks. The proposed system is able to support multi-Gb/s transmission with high spectral efficiency....

  8. An Efficient Algorithm For Chinese Postman Walk on Bi-directed de Bruijn Graphs

    CERN Document Server

    Kundeti, Vamsi; Dinh, Hieu

    2010-01-01

    Sequence assembly from short reads is an important problem in biology. It is known that solving the sequence assembly problem exactly on a bi-directed de Bruijn graph or a string graph is intractable. However finding a Shortest Double stranded DNA string (SDDNA) containing all the k-long words in the reads seems to be a good heuristic to get close to the original genome. This problem is equivalent to finding a cyclic Chinese Postman (CP) walk on the underlying un-weighted bi-directed de Bruijn graph built from the reads. The Chinese Postman walk Problem (CPP) is solved by reducing it to a general bi-directed flow on this graph which runs in O(|E|2 log2(|V |)) time. In this paper we show that the cyclic CPP on bi-directed graphs can be solved without reducing it to bi-directed flow. We present a ?(p(|V | + |E|) log(|V |) + (dmaxp)3) time algorithm to solve the cyclic CPP on a weighted bi-directed de Bruijn graph, where p = max{|{v|din(v) - dout(v) > 0}|, |{v|din(v) - dout(v) < 0}|} and dmax = max{|din(v) - ...

  9. Microwave impedance matching strategies of an applicator supplied by a bi-directional magnetron waveguide launcher.

    Science.gov (United States)

    Roussy, Georges; Kongmark, Nils

    2003-01-01

    It is shown that a bi-directional waveguide launcher can be used advantageously for reducing the reflection coefficient mismatch of an input impedance of an applicator. In a simple bi-directional waveguide launcher, the magnetron is placed in the waveguide and generates a nominal field distribution with significant output impedance in both directions of the waveguide. If a standing wave is tolerated in the torus, which connects the launcher and the applicator, the power transfer from the magnetron to the applicator can be optimal, without using special matching devices. It is also possible to match the bi-directional launcher with two inductance stubs near the antenna of the magnetron and use them for supplying a two-input applicator without reflection.

  10. Transducer-type bi-directional linear ultrasonic motor and experiment

    Institute of Scientific and Technical Information of China (English)

    CHU Xiangcheng; CHEN Zaili

    2002-01-01

    A transducer-type bi-directional linear ultrasonic notor is presented. It has the features of flexible bi-directional drive, simple construction and easy control, etc. The characteristics parameters of the prototype are: frequency 21.46 kHz, maximum moving speed 400 mm/s under pre-load of 3.2 N, maximum thrust 2.1 N under pre-load of 1.6 N. The influence of phase shift and vibration amplitude of ultrasonic transducers on ideal elliptical locus and output characteristics are investigated with theoretical and experimental methods.

  11. Ac-dc Bus-interface Bi-directional Converters in Renewable Energy Systems

    OpenAIRE

    Dong, Dong

    2012-01-01

    This dissertation covers several issues related to the ac-dc bus-interface bi-directional converters in renewable energy systems. The dissertation explores a dc-electronic distribution system for residential and commercial applications with a focus on the design of an ac-dc bi-directional converter for such application. This converter is named as the â Energy Control Centerâ due to its unique role in the system. First, the impact of the unbalanced power from the ac grid, especially the ...

  12. A Theory of Local Matching: SIFT and Beyond

    OpenAIRE

    Mobahi, Hossein; Soatto, Stefano

    2016-01-01

    Why has SIFT been so successful? Why its extension, DSP-SIFT, can further improve SIFT? Is there a theory that can explain both? How can such theory benefit real applications? Can it suggest new algorithms with reduced computational complexity or new descriptors with better accuracy for matching? We construct a general theory of local descriptors for visual matching. Our theory relies on concepts in energy minimization and heat diffusion. We show that SIFT and DSP-SIFT approximate the solutio...

  13. Longitudinal Bi-Directional Relationships between Sleep and Youth Substance Use

    Science.gov (United States)

    Pasch, Keryn E.; Latimer, Lara A.; Cance, Jessica Duncan; Moe, Stacey G.; Lytle, Leslie A.

    2012-01-01

    Despite the known deficits in sleep that occur during adolescence and the high prevalence of substance use behaviors among this group, relatively little research has explored how sleep and substance use may be causally related. The purpose of this study was to explore the longitudinal bi-directional relationships between sleep duration, sleep…

  14. Properties and Stability of Max-Product Fuzzy Bi-Directional Associative Memory

    Institute of Scientific and Technical Information of China (English)

    SHU Lan

    2005-01-01

    In this paper, a fuzzy operator of max-product is defined at first, and the fuzzy bi-directional associative memory (FBAM) based on the fuzzy operator of max-product is given. Then the properties and the Lyapunov stability of equilibriums of the networks are studied.

  15. Achievable rate regions and outer bounds for a multi-pair bi-directional relay network

    CERN Document Server

    Kim, Sang Joon; Devroye, Natasha

    2010-01-01

    In a bi-directional relay channel, a pair of nodes wish to exchange independent messages over a shared wireless half-duplex channel with the help of relays. Recent work has mostly considered information theoretic limits of the bi-directional relay channel with two terminal nodes (or end users) and one relay. In this work we consider bi-directional relaying with one base station, multiple terminal nodes and one relay, all of which operate in half-duplex modes. We assume that each terminal node communicates with the base-station in a bi-directional fashion through the relay and do not place any restrictions on the channels between the users, relays and base-stations; that is, each node has a direct link with every other node. Our contributions are three-fold: 1) the introduction of four new temporal protocols which fully exploit the two-way nature of the data and outperform simple routing or multi-hop communication schemes by carefully combining network coding, random binning and user cooperation which exploit ...

  16. Analysis of Bi-directional Effects on the Response of a Seismic Base Isolation System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyung-Kui; Kim, Jung-Han; Kim, Min Kyu; Choi, In-Kil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The floor response spectrum depends on the height of the floor of the structure. Also FRS depends on the characteristics of the seismic base isolation system such as the natural frequency, damping ratio. In the previous study, the floor response spectrum of the base isolated structure was calculated for each axis without considering bi-directional effect. However, the shear behavior of the seismic base isolation system of two horizontal directions are correlated each other by the bi-directional effects. If the shear behavior of the seismic isolation system changes, it can influence the floor response spectrum and displacement response of isolators. In this study, the analysis of a bi-directional effect on the floor response spectrum was performed. In this study, the response of the seismic base isolation system based on the bi-directional effects was analyzed. By analyzing the time history result, while there is no alteration in the maximum shear force of seismic base isolation system, it is confirmed that the shear force is generally more decreased in a one-directional that in a two-directional in most parts. Due to the overall decreased shear force, the floor response spectrum is more reduced in a two-directional than in a one-directional.

  17. Inferring bi-directional interactions between circadian clock genes and metabolism with model ensembles

    NARCIS (Netherlands)

    Grzegorczyk, Marco; Aderhold, Andrej; Husmeier, Dirk

    2015-01-01

    There has been much interest in reconstructing bi-directional regulatory networks linking the circadian clock to metabolism in plants. A variety of reverse engineering methods from machine learning and computational statistics have been proposed and evaluated. The emphasis of the present paper is on

  18. Flip-invariant SIFT for copy and object detection.

    Science.gov (United States)

    Zhao, Wan-Lei; Ngo, Chong-Wah

    2013-03-01

    Scale-invariant feature transform (SIFT) feature has been widely accepted as an effective local keypoint descriptor for its invariance to rotation, scale, and lighting changes in images. However, it is also well known that SIFT, which is derived from directionally sensitive gradient fields, is not flip invariant. In real-world applications, flip or flip-like transformations are commonly observed in images due to artificial flipping, opposite capturing viewpoint, or symmetric patterns of objects. This paper proposes a new descriptor, named flip-invariant SIFT (or F-SIFT), that preserves the original properties of SIFT while being tolerant to flips. F-SIFT starts by estimating the dominant curl of a local patch and then geometrically normalizes the patch by flipping before the computation of SIFT. We demonstrate the power of F-SIFT on three tasks: large-scale video copy detection, object recognition, and detection. In copy detection, a framework, which smartly indices the flip properties of F-SIFT for rapid filtering and weak geometric checking, is proposed. F-SIFT not only significantly improves the detection accuracy of SIFT, but also leads to a more than 50% savings in computational cost. In object recognition, we demonstrate the superiority of F-SIFT in dealing with flip transformation by comparing it to seven other descriptors. In object detection, we further show the ability of F-SIFT in describing symmetric objects. Consistent improvement across different kinds of keypoint detectors is observed for F-SIFT over the original SIFT.

  19. SIFT based algorithm for point feature tracking

    Directory of Open Access Journals (Sweden)

    Adrian BURLACU

    2007-12-01

    Full Text Available In this paper a tracking algorithm for SIFT features in image sequences is developed. For each point feature extracted using SIFT algorithm a descriptor is computed using information from its neighborhood. Using an algorithm based on minimizing the distance between two descriptors tracking point features throughout image sequences is engaged. Experimental results, obtained from image sequences that capture scaling of different geometrical type object, reveal the performances of the tracking algorithm.

  20. Efficient parallel and out of core algorithms for constructing large bi-directed de Bruijn graphs

    Directory of Open Access Journals (Sweden)

    Vaughn Matthew

    2010-11-01

    Full Text Available Abstract Background Assembling genomic sequences from a set of overlapping reads is one of the most fundamental problems in computational biology. Algorithms addressing the assembly problem fall into two broad categories - based on the data structures which they employ. The first class uses an overlap/string graph and the second type uses a de Bruijn graph. However with the recent advances in short read sequencing technology, de Bruijn graph based algorithms seem to play a vital role in practice. Efficient algorithms for building these massive de Bruijn graphs are very essential in large sequencing projects based on short reads. In an earlier work, an O(n/p time parallel algorithm has been given for this problem. Here n is the size of the input and p is the number of processors. This algorithm enumerates all possible bi-directed edges which can overlap with a node and ends up generating Θ(nΣ messages (Σ being the size of the alphabet. Results In this paper we present a Θ(n/p time parallel algorithm with a communication complexity that is equal to that of parallel sorting and is not sensitive to Σ. The generality of our algorithm makes it very easy to extend it even to the out-of-core model and in this case it has an optimal I/O complexity of Θ(nlog(n/BBlog(M/B (M being the main memory size and B being the size of the disk block. We demonstrate the scalability of our parallel algorithm on a SGI/Altix computer. A comparison of our algorithm with the previous approaches reveals that our algorithm is faster - both asymptotically and practically. We demonstrate the scalability of our sequential out-of-core algorithm by comparing it with the algorithm used by VELVET to build the bi-directed de Bruijn graph. Our experiments reveal that our algorithm can build the graph with a constant amount of memory, which clearly outperforms VELVET. We also provide efficient algorithms for the bi-directed chain compaction problem. Conclusions The bi-directed

  1. Tissue Microarray Study of Vasculogenic Mimicry in Bi-directional Differentiated Malignant Tumors

    Institute of Scientific and Technical Information of China (English)

    XishanHao; BaocunSun; ShiwuZhang; XiulanZhao

    2004-01-01

    OBJECTIVE To determine if vasculogenic mimicry (VM) exists in bi-directional differentiated malignant tumors. METHODS The blood supply models for bi-directional differentiated tumors were studied with immunohistochemical and PAS double-staining techniques. New sections were made from 158 paraffin-embedded bi-directional malignant-tumor samples, including melanoma (high malignancy n=30, low malignancy n=30); synoviosarcoma(SS) (high malignancy n=26, low malignancy n=13); acinar rhabdomyosarcoma (All) (high malignancy n=16,low malignancy n=13); malignant mesothelioma (MM) (n=26), and epithelioid sarcoma (ES)(n=4). Tissue microarrays were made. The representative points in the paraffin sections were labeled and two tissue microarrays were made, one included 60 cases of melanoma, and the other included the other tumors. Immunohistochemical staining of the platelet-endothelial cell adhesive molecule(CD31 antigen) and periodic acid Schiff(PAS) staining were conducted. The areas were calculated of vessel-like channels consisting of CD31 antigen-positive tumor cells and of PAS positive materials. The VM was studied using the data obtained. RESULTS Some of these bi-directional tumor cells secreted PAS-positive materials and 0D31 positive materials. The walls of the VM consisted of PAS-positive materials lined with CD31 negative tumor cells with red blood cells inside the channel, whereas the walls of the epithelium-dependent vessels were comprised of CD31 positive materials. The positive areas of CD31 were significantly less than that of PAS (P<0.01). The number of cases with VM in highly malignant tumors was greater than that found in the lowly malignant tumors. CONCLUSIONS Bi-directional differentiated malignant tumor cells have the ability to auto-transform and might interact with the extracellular matrix to form a vessel channel system which mimics blood vessels for transporting blood. That process is called VM. Results in this study show that bi-directional

  2. Identification of a bi-directional promoter from Tomato yellow leaf curl China virus

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A bi-directional promoter of Tomato yellow leaf curl China virus (TYLCCNV) was obtained with the total DNA from TYLCCNV isolate Y10 infected tobacco leaves as a template. Plant expression vectors were constructed by fusing the amplified DNA fragment with the gus gene and nopaline terminator in different orientations. The vectors containing promoter fragments were transferred into leaf cells and plant stems of Nicotiana benthamiana by Agrobacterium-mediated method. Transient expression results showed that both the complementary and virion-sense promoters could drive the gus gene to express, and the GUS activity of the complementary-sense promoter was stronger than that of the virion-sense. Co-expression of the vector containing βC1 gene of TYLCCNV DNAβ with the vector containing a bi-directional promoter revealed that the βC1 protein has no impact on expression of either the virion- or the complementarysense promoter.

  3. Model of Bi-directional Flyback Converter for Hybrid AC/DC Distribution System

    Directory of Open Access Journals (Sweden)

    Riku Pasonen

    2013-12-01

    Full Text Available In this article, a simulation model and concept of two switch bi-directional isolated DC/DC converter is presented. Converter is based on flyback converter type. Also control method for voltage regulation with bi-directional power transfer is presented. Target application of the proposed converter was selected to be a hybrid AC/DC distribution system concept of which was briefly described. The requirement of galvanic isolation in the hybrid AC/DC concept comes from use of shared neutral wire; DC current runs with unbalanced part of AC current in neutral wire. Without galvanic isolation grounded neutral would cause short circuit if DC/DC converter is connected to three phase rectifier or inverter. Simulation was carried out with PSCAD electromagnetic transient simulator.

  4. Detailed string stability analysis for bi-directional optimal velocity model

    Institute of Scientific and Technical Information of China (English)

    郑亮

    2015-01-01

    The class of bi-directional optimal velocity models can describe the bi-directional looking effect that usually exists in the reality and is even enhanced with the development of the connected vehicle technologies. Its combined string stability condition can be obtained through the method of the ring-road based string stability analysis. However, the partial string stability about traffic fluctuation propagated backward or forward was neglected, which will be analyzed in detail in this work by the method of transfer function and its H∞norm from the viewpoint of control theory. Then, through comparing the conditions of combined and partial string stabilities, their relationships can make traffic flow be divided into three distinguishable regions, displaying various combined and partial string stability performance. Finally, the numerical experiments verify the theoretical results and find that the final displaying string stability or instability performance results from the accumulated and offset effects of traffic fluctuations propagated from different directions.

  5. Analysis of bi-directional piezoelectric-based converters for zero-voltage switching operation

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Zhang, Zhe; Andersen, Michael A. E.

    2016-01-01

    This paper deals with a thorough analysis of zerovoltage switching especially for bi-directional, inductorless, piezoelectric transformer-based switch-mode power supplies with a half-bridge topology. Practically, obtaining zero-voltage switching for all of the switches in a bi......-directional piezoelectric power converter is a difficult task. However, the analysis in this work will be convenient for overcoming this challenge. The analysis defines the zero-voltage region indicating the operating points whether or not soft switching can be met over the switching frequency and load range. For the first...... time, a comprehensive analysis is provided, which can be used as a design guideline for applying control techniques in order to drive switches in piezoelectric transformer-based converters. This study further conveys the proposed method to the region where all the switches can obtain soft switching...

  6. Bi-directional memory-based dialog translation The KEMDT approach

    CERN Document Server

    Lee, G; Lee, J H; Lee, Geunbae; Jung, Hanmin; Lee, Jong-Hyeok

    1995-01-01

    A bi-directional Korean/English dialog translation system is designed and implemented using the memory-based translation technique. The system KEMDT (Korean/English Memory-based Dialog Translation system) can perform Korean to English, and English to Korean translation using unified memory network and extended marker passing algorithm. We resolve the word order variation and frequent word omission problems in Korean by classifying the concept sequence element in four different types and extending the marker- passing-based-translation algorithm. Unlike the previous memory-based translation systems, the KEMDT system develops the bilingual memory network and the unified bi-directional marker passing translation algorithm. For efficient language specific processing, we separate the morphological processors from the memory-based translator. The KEMDT technology provides a hierarchical memory network and an efficient marker-based control for the recent example-based MT paradigm.

  7. Bi-directional triplexer with butterfly MMI coupler using SU-8 polymer waveguides

    Science.gov (United States)

    Mareš, David; Jeřábek, Vítězslav; Prajzler, Václav

    2015-01-01

    We report about a design of a bi-directional planar optical multiplex/demultiplex filter (triplexer) for the optical part of planar hybrid WDM bi-directional transceiver in fiber-to-the-home (FTTH) PON applications. The triplex lightwave circuit is based on the Epoxy Novolak Resin SU-8 waveguides on the silica-on-silicon substrate with Polymethylmethacrylate cladding layer. The triplexer is comprised of a linear butterfly concept of multimode interference (MMI) coupler separating downstream optical signals of 1490 nm and 1550 nm. For the upstream channel of 1310 nm, an additional directional coupler (DC) is used to add optical signal of 1310 nm propagating in opposite direction. The optical triplexer was designed and optimized using beam propagation method. The insertion losses, crosstalk attenuation, and extinction ratio for all three inputs/outputs were investigated. The intended triplexer was designed using the parameters of the separated DC and MMI filter to approximate the idealized direct connection of both devices.

  8. BI-DIRECTIONAL COHEN-GROSSBERG NEURAL NETWORK WITH DISCRETE TIME

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Discrete-time version of the bi-directional Cohen-Grossberg neural network is stud-ied in this paper. Some sufficient conditions are obtained to ensure the global exponen-tial stability of such networks with discrete time based on Lyapunov method. These results do not require the symmetry of the connection matrix and the monotonicity, boundedness and differentiability of the activation function.

  9. BI-DIRECTIONAL COHEN-GROSSBERG NEURAL NETWORK WITH DISCRETE TIME

    Institute of Scientific and Technical Information of China (English)

    Du Dejun; Chen Anping

    2009-01-01

    Discrete-time version of the bi-directional Cohen-Grossberg neural network is stu-died in this paper. Some sufficient conditions are obtained to ensure the global ex-ponential stability of such" networks with discrete time based on Lyapunov method. These results do not require the symmetry of the connection matrix and the monoto-nicity, boundedness and differentiability of the activation function.

  10. The Bi-directional Moving Structures in a Coronal Bright Point

    CERN Document Server

    Li, Dong; Su, Yingna

    2016-01-01

    We report the bi-directional moving structures in a coronal bright point (CBP) on 2015 July 14. It is observed by the Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO). This CBP has a lifetime of about 10 minutes, and a curved shape. The observations show that many bright structures are moving intermittently outward from the CBP brightness core. Such moving structures are clearly seen at AIA 171, 193, 211, 131, 94, 335 and 304 A, slit-jaw (SJI) 1330 and 1400 A. In order to analyze these moving structures, the CBP is cut along the moving direction with a curved slit from the AIA and SJI images. Then we can obtain the time-distance slices, including the intensity and intensity-derivative diagrams, from which, the moving structures are recognized as the oblique streaks, and they are characterized by the bi-direction, simultaneity, symmetry, and periodicity. The average speed is around 300 km/s, while the typically period is about 90 s. All these features (including the bi-directional fl...

  11. Development of an efficient bi-directional promoter with tripartite enhancer employing three viral promoters.

    Science.gov (United States)

    Patro, Sunita; Maiti, Indu B; Dey, Nrisingha

    2013-02-10

    We have developed a novel bi-directional promoter (FsFfCBD) by placing two heterogeneous core-promoters from the Figwort mosaic virus sub-genomic transcript promoter (FsCP, -69 to +31) and Cauliflower mosaic virus 35S promoter (CCP, -89 to +1) respectively on upstream (5') and downstream (3') ends of a tri-hybrid enhancer (FsEFfECE), in reverse orientation. The FsEFfECE domain encompasses three heterologous enhancer fragments from Figwort mosaic virus sub-genomic transcript promoter (FsE, 101 bp, -70 to -170), Figwort mosaic virus full-length transcript promoter (FfE, 196 bp, -249 to -54) and Cauliflower mosaic virus 35S promoter (CE, 254 bp, -343 to -90). The bi-directional nature of the FsFfCBD promoter (coupled to GFP and GUS) was established both in transient systems (onion epidermal cells and tobacco protoplasts) and transgenic plant (Nicotiana tabacum samsun NN) by monitoring the simultaneous expression of GFP and GUS employing fluorescence (for GFP) and biochemical (for GUS) based assays. In transgenic plants, the FsFfCBD promoter was found to be 6.8 and 2.5 times stronger than two parent promoters; Fs and FfC respectively. The bi-directional compound promoter FsFfCBD, composed of three heterologous enhancers with enhanced activity could become a valuable additional tool for efficient plant metabolic engineering and molecular pharming.

  12. Bi-directional electrons in the near-Earth plasma sheet

    Directory of Open Access Journals (Sweden)

    K. Shiokawa

    Full Text Available We have studied the occurrence characteristics of bi-directional electron pitch angle anisotropy (enhanced flux in field-aligned directions, F^ /F|| > 1.5 at energies of 0.1–30 keV using plasma and magnetic field data from the AMPTE/IRM satellite in the near-Earth plasma sheet. The occurrence rate increases in the tailward direction from XGSM = - 9 RE to - 19 RE . The occurrence rate is also enhanced in the midnight sector, and furthermore, whenever the elevation angle of the magnetic field is large while the magnetic field intensity is small, B ~ 15 nT. From these facts, we conclude that the bi-directional electrons in the central plasma sheet are produced mainly in the vicinity of the neutral sheet and that the contribution from ionospheric electrons is minor. A high occurrence is also found after earthward high-speed ion flows, suggesting Fermi-type field-aligned electron acceleration in the neutral sheet. Occurrence characteristics of bi-directional electrons in the plasma sheet boundary layer are also discussed.

    Key words. Magnetospheric physics (magnetospheric configuration and dynamics; magnetotail; plasma sheet

  13. Sifting of waste; Siktning av avfall

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Andreas [SP Technical Research Inst. of Sweden, Boraas (Sweden); Johnsson, Anders [Boraas Energi och Miljoe, Boraas (Sweden); Yoshiguchi, Hitomi [Stena Metall, Goeteborg (Sweden); Steenari, Britt-Marie [Chalmers Tekniska Hoegskola, Goeteborg (Sweden); Bostroem, Sara [Renova AB, Goeteborg (Sweden); Fredaeng, Julia [Dalkia, Stockholm (Sweden); Bisaillon, Mattias [Profu AB, Moelndal (Sweden); Andersson, Hans [Metso Power, Tammerfors (Finland)

    2008-08-15

    Waste as a fuel is characterized by high levels of inert components (ash) that may cause problems in a combustion process that result in high costs for operation and maintenance (e.g. large ash flows, high need for additives). A potential method for reduction of these costs is to separate inert components through sifting prior the combustion process. Previously it has been found that a major share of the unwanted components is found in the fine grains. However, the practical relevance of sifting has not been verified against boiler performance. Therefore, the prospects for sifting as a pre-treatment method was investigated at Boraas Energi och miljoe with the aim to characterize the composition in the fine-grained residues and to determine the effects from sifting on the boiler performance. The project includes also a short report on possible markets for the fine-grained residues. The effect target is to increase the boiler availability and to reduce the cost for operation and maintenance. The target groups for the work are owners of Energy-from-Waste plants as well as constructors of plants and sieves. The work shows that sifting can be beneficial from an economical point of view if a suitable market for the fine-grained residues is found. Several theoretical markets exist but the governing parameter is the actual costs for the post-treatment.

  14. Performability evaluation of the SIFT computer

    Science.gov (United States)

    Meyer, J. F.; Furchtgott, D. G.; Wu, L. T.

    1979-01-01

    Performability modeling and evaluation techniques are applied to the SIFT computer as it might operate in the computational evironment of an air transport mission. User-visible performance of the total system (SIFT plus its environment) is modeled as a random variable taking values in a set of levels of accomplishment. These levels are defined in terms of four attributes of total system behavior: safety, no change in mission profile, no operational penalties, and no economic process whose states describe the internal structure of SIFT as well as relavant conditions of the environment. Base model state trajectories are related to accomplishment levels via a capability function which is formulated in terms of a 3-level model hierarchy. Performability evaluation algorithms are then applied to determine the performability of the total system for various choices of computer and environment parameter values. Numerical results of those evaluations are presented and, in conclusion, some implications of this effort are discussed.

  15. Domain-Size Pooling in Local Descriptors: DSP-SIFT

    OpenAIRE

    Dong, Jingming; Soatto, Stefano

    2014-01-01

    We introduce a simple modification of local image descriptors, such as SIFT, based on pooling gradient orientations across different domain sizes, in addition to spatial locations. The resulting descriptor, which we call DSP-SIFT, outperforms other methods in wide-baseline matching benchmarks, including those based on convolutional neural networks, despite having the same dimension of SIFT and requiring no training.

  16. Measurement of SIFT operating system overhead

    Science.gov (United States)

    Palumbo, D. L.; Butler, R. W.

    1985-01-01

    The overhead of the software implemented fault tolerance (SIFT) operating system was measured. Several versions of the operating system evolved. Each version represents different strategies employed to improve the measured performance. Three of these versions are analyzed. The internal data structures of the operating systems are discussed. The overhead of the SIFT operating system was found to be of two types: vote overhead and executive task overhead. Both types of overhead were found to be significant in all versions of the system. Improvements substantially reduced this overhead; even with these improvements, the operating system consumed well over 50% of the available processing time.

  17. Sifting attacks in finite-size quantum key distribution

    Science.gov (United States)

    Pfister, Corsin; Lütkenhaus, Norbert; Wehner, Stephanie; Coles, Patrick J.

    2016-05-01

    A central assumption in quantum key distribution (QKD) is that Eve has no knowledge about which rounds will be used for parameter estimation or key distillation. Here we show that this assumption is violated for iterative sifting, a sifting procedure that has been employed in some (but not all) of the recently suggested QKD protocols in order to increase their efficiency. We show that iterative sifting leads to two security issues: (1) some rounds are more likely to be key rounds than others, (2) the public communication of past measurement choices changes this bias round by round. We analyze these two previously unnoticed problems, present eavesdropping strategies that exploit them, and find that the two problems are independent. We discuss some sifting protocols in the literature that are immune to these problems. While some of these would be inefficient replacements for iterative sifting, we find that the sifting subroutine of an asymptotically secure protocol suggested by Lo et al (2005 J. Cryptol. 18 133-65), which we call LCA sifting, has an efficiency on par with that of iterative sifting. One of our main results is to show that LCA sifting can be adapted to achieve secure sifting in the finite-key regime. More precisely, we combine LCA sifting with a certain parameter estimation protocol, and we prove the finite-key security of this combination. Hence we propose that LCA sifting should replace iterative sifting in future QKD implementations. More generally, we present two formal criteria for a sifting protocol that guarantee its finite-key security. Our criteria may guide the design of future protocols and inspire a more rigorous QKD analysis, which has neglected sifting-related attacks so far.

  18. An improved SIFT algorithm based on KFDA in image registration

    Science.gov (United States)

    Chen, Peng; Yang, Lijuan; Huo, Jinfeng

    2016-03-01

    As a kind of stable feature matching algorithm, SIFT has been widely used in many fields. In order to further improve the robustness of the SIFT algorithm, an improved SIFT algorithm with Kernel Discriminant Analysis (KFDA-SIFT) is presented for image registration. The algorithm uses KFDA to SIFT descriptors for feature extraction matrix, and uses the new descriptors to conduct the feature matching, finally chooses RANSAC to deal with the matches for further purification. The experiments show that the presented algorithm is robust to image changes in scale, illumination, perspective, expression and tiny pose with higher matching accuracy.

  19. Study on Application of Bi-directional Combination Technology Integrating Residue Hydrotreating with Catalytic Cracking RICP

    Institute of Scientific and Technical Information of China (English)

    Niu Chuanfeng; Gao Yongcan; Dai Lishun; Li Dadong

    2008-01-01

    After analysing the disadvantages of the traditional residue hydrotreating-catalytic cracking combination process, RIPP has proposed a bi-directional combination technology integrating residue hydrotreating with catalytic cracking called RICP which does not further recycles the FCC heavy cycle oil (HCO) inside the FCC unit and delivers HCO to the residue hydrotreating unit as a diluting oil for the residue that is concurrently subjected to hydrotreating prior to being used as the FCC feed oil. The RICP technology can stimulate residue hydrotreating reactions through utilization of HCO along with an increased yield of FCC light distillate, resulting in enhanced petroleum utilization and economic benefits of the refinery.

  20. Reliability analysis of an LCL tuned track segmented bi-directional inductive power transfer system

    DEFF Research Database (Denmark)

    Asif Iqbal, S. M.; Madawala, U. K.; Thrimawithana, D. J.;

    2013-01-01

    Bi-directional Inductive Power Transfer (BDIPT) technique is suitable for renewable energy based applications such as electric vehicles (EVs), for the implementation of vehicle-to-grid (V2G) systems. Recently, more efforts have been made by researchers to improve both efficiency and reliability...... for a 1.5 kW BDIPT system in a MATLAB/Simulink environment. Reliability parameters such as failure rate and mean time between failures (MTBF) are compared between the two systems. A nonlinear programming (NP) model is developed for optimizing charging schedule for a stationery EV. A case study of EV...

  1. Analysis of global exponential stability for a class of bi-directional associative memory networks

    Institute of Scientific and Technical Information of China (English)

    王宏霞; 何晨

    2003-01-01

    In real-time applications of bi-directional associative memory (BAM) networks, a global exponentially stable equilibrium is highly desired. The existence, uniqueness and global exponential stability for a class of BAM networks are studied in this paper, the signal function of neurons is assumed to be piece-wise linear from the engineering point of view. A very concise condition for the equilibrium of such a network being globally exponentially stable is derived,which makes the practical design of this kind of networks an easy job.

  2. SAR-SIFT: A SIFT-LIKE ALGORITHM FOR SAR IMAGES

    OpenAIRE

    Dellinger, Flora; Delon, Julie; Gousseau, Yann; Michel, Julien; Tupin, Florence

    2015-01-01

    International audience; The Scale Invariant Feature Transform (SIFT) algorithm is widely used in computer vision to match features between images or to localize and recognize objets. However, mostly because of speckle noise, it does not perform well on synthetic aperture radar (SAR) images. We present here an improvement of this algorithm for SAR images, named SAR-SIFT. A new gradient computation, yielding an orientation and a magnitude robust to speckle noise, is first introduced. It is then...

  3. Fault tolerant software modules for SIFT

    Science.gov (United States)

    Hecht, M.; Hecht, H.

    1982-01-01

    The implementation of software fault tolerance is investigated for critical modules of the Software Implemented Fault Tolerance (SIFT) operating system to support the computational and reliability requirements of advanced fly by wire transport aircraft. Fault tolerant designs generated for the error reported and global executive are examined. A description of the alternate routines, implementation requirements, and software validation are included.

  4. Projecting Ammonia Dry Deposition Using Passive Samplers and a Bi-Directional Exchange Model

    Science.gov (United States)

    Robarge, W. P.; Walker, J. T.; Austin, R. E.

    2011-12-01

    Animal agriculture within the United States is known to be a source of ammonia (NH3) emissions. Dry deposition of NH3 to terrestrial ecosystems immediately surrounding large local sources of NH3 emissions (e.g. animal feeding operations) is difficult to measure, and is best estimated via models. Presented here are results for a semi-empirical modeling approach for estimating air-surface exchange fluxes of NH3 downwind of a large poultry facility (~ 3.5 million layers) using a bi-directional air-surface exchange model. The modeling domain is the western section of the Pocosin Lakes National Wildlife Refuge in Tyrrell, Washington, and Hyde Counties of eastern North Carolina in the South Atlantic Coastal Plain physiographic region. Vegetation within the modeling domain is primarily pocosin wetlands, characterized by acid (pH 3.6) peat soils and a thick canopy of shrub vegetation (leatherwood (Cyrilla racemiflora), inkberry (Ilex glabra), wax myrtle (Morella cerifera)). Land surrounding the refuge is primarily used for crop production: ~ 28%, 24%, and 45% agricultural in Tyrell, Hyde, and Washington counties, respectively. Ammonia air-surface exchange (flux) was calculated using a two-layer canopy compensation point model developed by Nemitz et al. (2001. Quart. J. Roy. Met. Soc. 127, 815 - 833.) as implemented by Walker et al. (2008. Atmos. Environ., 42, 3407 - 3418.), in which the competing processes of emission and deposition within the foliage-soil system were taken into account by relating the net canopy-scale NH3 flux to the net emission potential of the canopy (i.e., foliage and soil). Ammonia air concentrations were measured using ALPHA passive samplers (Center for Ecology and Hydrology, Edinburgh) along transects to the north and northeast of the poultry facility at distances of 800, 2000 and 3200 m, respectively. Samplers were deployed in duplicate at each location at a height of 5.8 m from July 2008 to July 2010 weekly during warm months and bi-weekly curing

  5. A mathematical model and computational framework for three-dimensional chondrocyte cell growth in a porous tissue scaffold placed inside a bi-directional flow perfusion bioreactor.

    Science.gov (United States)

    Shakhawath Hossain, Md; Bergstrom, D J; Chen, X B

    2015-12-01

    The in vitro chondrocyte cell culture for cartilage tissue regeneration in a perfusion bioreactor is a complex process. Mathematical modeling and computational simulation can provide important insights into the culture process, which would be helpful for selecting culture conditions to improve the quality of the developed tissue constructs. However, simulation of the cell culture process is a challenging task due to the complicated interaction between the cells and local fluid flow and nutrient transport inside the complex porous scaffolds. In this study, a mathematical model and computational framework has been developed to simulate the three-dimensional (3D) cell growth in a porous scaffold placed inside a bi-directional flow perfusion bioreactor. The model was developed by taking into account the two-way coupling between the cell growth and local flow field and associated glucose concentration, and then used to perform a resolved-scale simulation based on the lattice Boltzmann method (LBM). The simulation predicts the local shear stress, glucose concentration, and 3D cell growth inside the porous scaffold for a period of 30 days of cell culture. The predicted cell growth rate was in good overall agreement with the experimental results available in the literature. This study demonstrates that the bi-directional flow perfusion culture system can enhance the homogeneity of the cell growth inside the scaffold. The model and computational framework developed is capable of providing significant insight into the culture process, thus providing a powerful tool for the design and optimization of the cell culture process.

  6. Review and parameterisation of bi-directional ammonia exchange between vegetation and the atmosphere

    Science.gov (United States)

    Massad, R.-S.; Nemitz, E.; Sutton, M. A.

    2010-11-01

    Current deposition schemes used in atmospheric chemical transport models do not generally account for bi-directional exchange of ammonia (NH3). Bi-directional exchange schemes, which have so far been applied at the plot scale, can be included in transport models, but need to be parameterised with appropriate values of the ground layer compensation point (χg), stomatal compensation point (χs) and cuticular resistance (Rw). We review existing measurements of χg, χs as well as Rw and compile a comprehensive dataset from which we then propose generalised parameterisations. χs is related to Γs, the non-dimensional ratio of [NH4+]apo and [H+]apo in the apoplast, through the temperature dependence of the combined Henry and dissociation equilibrium. The meta-analysis suggests that the nitrogen (N) input is the main driver of the apoplastic and bulk leaf concentrations of ammonium (NH4 apomodel for example). In principle, the parameterisations should be applicable to other climates, though there is a need for more underpinning data, with the uncertainties being especially large for tropical and subtropical conditions.

  7. [Differences of bi-directional regulative effects between acu-moxibustion and Chinese materia medica interventions].

    Science.gov (United States)

    Cao, Xin; Yu, Zhi; Xu, Bin

    2012-10-01

    Bi-directional regulation is referred to a balancing effect of both acu-moxibustion and Chinese materia medica interventions when the human body is experiencing a hyperactivity or hypoactivity due to abnormal intrinsic or external factors. In the present paper, the authors analyze their identical and different characteristics from: 1) definition; 2) characters of regulative effects of acu-moxibustion therapy: A) differentiation of meridian and zangfu-organs being the basis of treatment, B) four factors (acupoint-location, body's functional state, acupoint-formula and needle-manipulation techniques) dependant, C) entirety regulation, and D) centrotaxis modulation; 3) characters of Chinese materia medica intervention: including a) correspondence between the drug property and the syndrome being the basis of the regulative effect, b) multi-factors [components (antagonist and agonist), combination, dosages and processing quality of Chinese materia medica, and functional state of the human body] dependant, c) entirety regulation, and d) both centrotaxis and deviation adjustment. In one word, the bi-directional regulation effect is one of the basic characteristics of both acu-moxibustion and Chinese materia medica in clinical practice, but their basis and modes for inducing effects are different.

  8. Elderly fall detection using SIFT hybrid features

    Science.gov (United States)

    Wang, Xiaoxiao; Gao, Chao; Guo, Yongcai

    2015-10-01

    With the tendency of aging society, countries all over the world are dealing with the demographic change. Fall had been proven to be of the highest fatality rate among the elderly. To realize the elderly fall detection, the proposed algorithm used the hybrid feature. Based on the rate of centroid change, the algorithm adopted VEI to offer the posture feature, this combined motion feature with posture feature. The algorithm also took advantage of SIFT descriptor of VEI(V-SIFT) to show more details of behaviors with occlusion. An improved motion detection method was proposed to improve the accuracy of front-view motion detection. The experimental results on CASIA database and self-built database showed that the proposed approach has high efficiency and strong robustness which effectively improved the accuracy of fall detection.

  9. Diffuse and bi-directional reflectance spectrometry to study European volcanic soils

    Directory of Open Access Journals (Sweden)

    Roberto Salzano

    2008-01-01

    Full Text Available Diffuse and bi-directional reflectance spectroscopy were applied in this research in order to characterize chemical and mineralogical properties in volcanic soils. The study was conducted on 77 volcanic soil profiles from several European countries. Diffuse reflectance spectroscopy was used in conjunction with parameterization using the second derivative of the Kubelka-Munk function and colour calculation. From derivative curves, one band of interest was characterized and identified around 450 nm. Using correlation analysis, significant relationships were observed between amplitude of this band and Fed (r = 0.6. In addition, the data showed that soil organic matter content, Ald and Fep were moderately correlated with reflectance values centered at 546, 579 and 2048 nm.

  10. Bi-directional conversion between microwave and optical frequencies in a piezoelectric optomechanical device

    Science.gov (United States)

    Vainsencher, Amit; Satzinger, K. J.; Peairs, G. A.; Cleland, A. N.

    2016-07-01

    We describe the principles of design, fabrication, and operation of a piezoelectric optomechanical crystal with which we demonstrate bi-directional conversion of energy between microwave and optical frequencies. The optomechanical crystal has an optical mode at 1523 nm co-located with a mechanical breathing mode at 3.8 GHz, with a measured optomechanical coupling strength gom/2π of 115 kHz. The breathing mode is driven and detected by curved interdigitated transducers that couple to a Lamb mode in suspended membranes on either end of the optomechanical crystal, allowing the external piezoelectric modulation of the optical signal as well as the converse, the detection of microwave electrical signals generated by a modulated optical signal. We compare measurements to theory where appropriate.

  11. Power system transient stability simulation based on module bi-directional iteration

    Institute of Scientific and Technical Information of China (English)

    FANG; Dazhong; YANG; Xiaodong

    2005-01-01

    A new simultaneous solution method using module bi-directional iteration is proposed for power system transient stability simulation. In this method, power network is partitioned into a tree hierarchy; computation modules are established for decomposed power networks and various power system components respectively. Through representing every computation module by a computation node, a computation tree is constructed by connecting the nodes together according to their electrical relations in power systems. A tree-traversing procedure called forward reduction and backward evaluation is performed to calculate correction factors of the variables in Newton iterations. This high-efficiency simulation method is feasible to be applied in parallel computation for large interconnected systems. Simulation tests are conducted on the New England 10-generator test power system and the North China-Northeast interconnected system, and the results are compared with those of the commercial software BPA to validate the effectiveness and correctness of this method.

  12. Demonstration and experimental evaluation of a bi-directional 10-GHz microwave photonic filter

    Science.gov (United States)

    Zaldívar-Huerta, I. E.; Correa-Mena, A. G.; Hernández-Nava, P.; García-Juárez, A.; Rodríguez-Asomoza, J.; Lee, Min Won

    2016-09-01

    A bi-directional 10-GHz microwave photonic filter is proposed and experimentally evaluated. Its frequency response consists of a series of microwave band-pass windows obtained by the interaction of externally modulated multimode laser diodes emitting around of 1550 nm associated to the chromatic dispersion parameter of an optical fiber, as well as the length of the optical link. Microwave band-pass windows exhibit on average a-3 dB bandwidth of 378 MHz. This electro-optical system shows an efficient configuration and good performance. Potentially, filtered microwave signals can be used as electrical carriers in optical communication systems to transmit and distribute services such as video, voice and data.

  13. A possible mechanism for self coordination of bi-directional traffic across nuclear pores

    CERN Document Server

    Kapon, Ruti; Mukamel, David; Reich, and Ziv

    2008-01-01

    Nuclear pore complexes are constantly confronted by large fluxes of macromolecules and macromolecular complexes that need to get into and out of the nucleus. Such bi-directional traffic occurring in a narrow channel can easily lead to jamming. How then is passage between the nucleus and cytoplasm maintained under the varying conditions that arise during the lifetime of the cell? Here, we address this question using computer simulations in which the behaviour of the ensemble of transporting cargoes is analyzed under different conditions. We suggest that traffic can exist in two distinct modes, depending on concentration of cargoes and dissociation rates of the transport receptor-cargo complexes from the pores. In one mode, which prevails when dissociation is quick and cargo concentration is low, transport in either direction proceeds uninterrupted by the other direction. The result is that overall-traffic-direction fluctuates rapidly and unsystematically between import and export. Remarkably, when cargo concen...

  14. CSO/CTB/BER performances improvement in a bi-directional hybrid DWDM system

    Institute of Scientific and Technical Information of China (English)

    Hai-Han Lu(吕海涵); Hsu-Hung Huang(黄旭弘); Ming-Chuan Wang(王明傅); Heng-Sheng Su(蘇(恒)生)

    2003-01-01

    Experimental verifications of the feasibility of using chirped fiber grating (CFG) as the dispersion compen-sation device in a bi-directional hybrid dense-wavelength-division-multiplexing (DWDM) system to reducethe dispersion and cross-phase modulation (XPM) induced crosstalk were proposed and demonstrated.Not only channel capacity was increased, but also good performances of carrier-to-noise ratio (CNR) ≥ 50dB, composite second order (CSO) ≥72 dB, composite triple beat (CTB) ≥69 dB and low bit error rate(BER) < 10-9 were achieved in our proposed system over a 50-km single-mode fiber (SMF) transport.

  15. Hybrid semiconductor-dielectric metamaterial modulation for switchable bi-directional THz absorbers

    Science.gov (United States)

    Le, Ly Nguyen; Thang, Nguyen Manh; Thuy, Le Minh; Tung, Nguyen Thanh

    2017-01-01

    There is an increasing interest for electromagnetic metamaterials that show mutable absorption properties with real-time and dynamic control. In this paper, we investigate a modulation of bi-directional metamaterial absorbers that is thermally switchable at terahertz frequencies. The metamaterial absorber is composed of symmetric hybrid semiconductor-dielectric cut-wire-pair structures, whose electromagnetic responses can be actively manipulated by utilizing an external heat source. As increasing the temperature of metamaterials from 300 to 350 K, we demonstrate that the magnetic resonance can be systematically blue-shifted and overlapped with the electric resonance, which is unaffectedly settled at about 0.8 THz. This superposition provides an effective mechanism to control the absorption intensity from 43% to nearly 95%. Finite integration simulation technique, standard retrieval method, and equivalent circuit model are employed to elaborate our idea.

  16. Bi-directional evolutionary topology optimization of continuum structures with one or multiple materials

    Science.gov (United States)

    Huang, X.; Xie, Y. M.

    2009-02-01

    There are several well-established techniques for the generation of solid-void optimal topologies such as solid isotropic material with penalization (SIMP) method and evolutionary structural optimization (ESO) and its later version bi-directional ESO (BESO) methods. Utilizing the material interpolation scheme, a new BESO method with a penalization parameter is developed in this paper. A number of examples are presented to demonstrate the capabilities of the proposed method for achieving convergent optimal solutions for structures with one or multiple materials. The results show that the optimal designs from the present BESO method are independent on the degree of penalization. The resulted optimal topologies and values of the objective function compare well with those of SIMP method.

  17. Dynamic Analyses of Isolated Structures under Bi-Directional Excitations of Near-Field Ground Motions

    Directory of Open Access Journals (Sweden)

    Gokhan Ozdemir

    2012-01-01

    Full Text Available Nonlinear response history analyses (NRHA of a 3-story isolated reinforced concrete (RC building are carried out under both uni- and bi-directional earthquake excitations of near-field records. NRHA are conducted for a wide range of yield strength (Q/W of lead rubber bearings (LRB, and isolation period (T. Selected near-field records are used to investigate both the contribution of orthogonal components on maximum isolator displacements and accuracy of equivalent lateral force (ELF procedure on estimation of maximum isolator displacements. Analyses results show that both the contribution of orthogonal components and accuracy of ELF procedure depend on the soil condition where isolation system is implemented.

  18. Regenerative Strategy for Sum-rate Enhancement in Bi-directional Three-node Cooperation

    Institute of Scientific and Technical Information of China (English)

    Hu Ning; Zhong Xiaofeng; Zhao Ming; Wang Jing

    2009-01-01

    In bi-directional three-node cooperation, one regenerative strategy with network coding and power optimization is proposed for system sum-rate under a total energy constraint. In this paper, the network coding and power optimization are applied to improve system sum-rate. But max-min optimization problem in power allocation is a NP-hard problem. In high Signal-to-Noise Ratio regime, this NP-hard problem is transformed into constrained polynomial optimization problem, which can be computed in polynomial time. Although it is a suboptimal solution, numerical simulations show that this strategy enhances the system sum-rate up to 45% as compared to a traditional four-phase strategy, and up to 13% as compared to the three-phase strategy without power optimization.

  19. A bi-directional gap model for simulating the directional thermal radiance of row crops

    Institute of Scientific and Technical Information of China (English)

    CHEN; Liangfu; (陈良富); LIU; Qinhuo; (柳钦火); FAN; Wenjie; (范闻捷); LI; Xiaowen; (李小文); XIAO; Qing; (肖青); YAN; Guangjian; (闫广建); TIAN; Guoliang; (田国良)

    2002-01-01

    Row crops are a kind of typical vegetation canopy between discrete canopy and continuous canopy. Kimes et al. studied the directional thermal radiation of row crops using the geometrical optical model, which simplified row structure as "box" and neglected the gap among foliage and did not consider the emissivity effects. In this work we take account of the gaps along illumination and viewing directions and propose a bi-direction gap model on the basis of the idea of gap probability of discrete vegetation canopy introduced by "Li-Strahler" and inter-correlation of continuous vegetation developed by Kuusk. It can be used to explain "hot spot" effects in thermal infrared region. The gap model has been validated by field experiment on winter wheat planted in shape of rows and results show that the gap model is better than Kimes' model in describing the directionality of thermal infrared emission for row crops.

  20. Inference of biological networks using Bi-directional Random Forest Granger causality.

    Science.gov (United States)

    Furqan, Mohammad Shaheryar; Siyal, Mohammad Yakoob

    2016-01-01

    The standard ordinary least squares based Granger causality is one of the widely used methods for detecting causal interactions between time series data. However, recent developments in technology limit the utilization of some existing implementations due to the availability of high dimensional data. In this paper, we are proposing a technique called Bi-directional Random Forest Granger causality. This technique uses the random forest regularization together with the idea of reusing the time series data by reversing the time stamp to extract more causal information. We have demonstrated the effectiveness of our proposed method by applying it to simulated data and then applied it to two real biological datasets, i.e., fMRI and HeLa cell. fMRI data was used to map brain network involved in deductive reasoning while HeLa cell dataset was used to map gene network involved in cancer.

  1. High efficiency interleaved bi-directional ZVS DC-DC converter

    Science.gov (United States)

    Zafarullah Khan, M.; Mohsin Naveed, M.; Akbar Hussain, D. M.

    2013-06-01

    A high efficiency interleaved bi-directional ZVS DC-DC converter is presented in this paper. This converter can be operated in both buck and boost mode. CoolMOS is used as a power device to achieve low conduction losses and fast turn off. The value of inductance is selected such that the CoolMOS drain-to-source voltage always falls to zero before it turns on and ZVS is achieved. Multiphase interleaved inductors are used to achieve high power and low ripple currents. Converter is operated at 50kHz and MATLAB Simulink simulation is performed. 6kW prototype converter is implemented in buck mode and simulation results are verified.

  2. Bi-directional two-dimensional/three-dimensional convertible integral imaging using scattering polarizer

    Science.gov (United States)

    Yeom, Jiwoon; Hong, Jisoo; Park, Soon-gi; Min, Sung-Wook; Lee, Byoungho

    2012-10-01

    A bi-directional 2D/3D convertible integral imaging system is proposed. Two optical modules composed of a scattering polarizer and a linear polarizer are adopted, and 2D or 3D mode operation is easily changed by converting polarization states of the projected images. In the 2D mode, the incident light is scattered at the scattering polarizer and the scattered light facing the lens-array is blocked, a 2D image is observable only at the same side as the projector. In the 3D mode, the incident light with the transmission polarization is directly projected onto a lens-array, and the 3D images are integrated. Our proposed system is able to display the 3D images as well as the 2D images for the observers who are placed in front and rear side of the system.

  3. An Image Encryption Scheme Based on Bit Circular Shift and Bi-directional Diffusion

    Directory of Open Access Journals (Sweden)

    Ruisong Ye

    2013-12-01

    Full Text Available A novel image encryption scheme based on chaotic system is proposed. The proposed encryption scheme utilizes one tent map to generate a pseudo-random sequence and then shift the bits of the expanding 0-1 image circularly so as to shuffle the image gray values. To make the encryption scheme resist differential attack efficiently, generalized Arnold maps and Bernoulli shift maps are applied to produce two pseudo-random gray value sequences and then diffuse the gray values bi-directionally. The bit circular shift process and diffusion processes greatly confuse the statistical nature between plain-images and cipher-images. Security analyses including key sensitivity analysis, key space analysis, statistical analysis, differential attack analysis and information entropy analysis are performed. All the experimental results demonstrate that the proposed image encryption scheme possesses large key space to frustrate brute-force attack efficiently and can resist statistical attack, differential attack, etc.

  4. A distributed optical fiber bi-directional strain-displacement sensor

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A distributed optical fiber strain-displacement sensor is developed, which consists of an optical fiber gauge of strain-displacement and an optical time domain reflectometer (OTDR). The operational principle is the modulation of fiber loss in OTDR, i.e. the strain and displacement in monitoring position are obtained from the bending loss of optical fiber bonded on the optical fiber gauge of strain-displacement. After examining the strain and displacement in the cantilever and the micro displacement rack respectively, the result indicates that the distributed optical fiber gauge of strain-displacement can monitor strains or displacements in different sensitive lengths. The key technique for measuring bi-directional strain-displacement is the pretreatment of bending of the freely suspended optical fibers, which can be identified with OTDR by inserting time delay optical fiber.

  5. An Experimental Investigation of the Responses of Classic Spar Platform Subjected to Bi-directional Waves

    Directory of Open Access Journals (Sweden)

    V.J. Kurian

    2015-01-01

    Full Text Available The effect of the bi-directional short-crested waves on the dynamic motion responses of the moored classic spar is demonstrated from the results of the models test in this study. Practically in the design of offshore structures, long-crested or 2-dimensional wave properties that propagated to one direction are considered. Even though such long-crested wave is widely used for the design purposes, it is hardly determined in the real sea. The wind generated sea state in the real sea conditions are indeed well represented by the short-crested waves. Short-crested waves are defined as linear summation of long-crested wave series that propagated to different directions. Hence, the motions of the model were investigated experimentally by conducting the wave tank tests in the wave tank of Offshore Laboratory of Universiti Teknologi PETRONAS. Five groups of bi-directional wave series were defined and exerted on the classic spar model, which fabricated by using steel with scaling factor of 1:100. From the results measured, it was found that similar trends of the responses in term of Response Amplitude Operator (RAO for surge, heave and pitch motions were obtained. Maximum responses of surge, heave and pitch were found due to wave crossing angle 90°, while minimum response was found due to wave crossing angle 135°, respectively. It could be concluded that the wave crossing angle 90° (BD3 gives the widest spreading for short crested waves, while the wave crossing angle 135° (BD4 gives the narrowest spreading for short crested waves.

  6. Software Implemented Fault-Tolerant (SIFT) user's guide

    Science.gov (United States)

    Green, D. F., Jr.; Palumbo, D. L.; Baltrus, D. W.

    1984-01-01

    Program development for a Software Implemented Fault Tolerant (SIFT) computer system is accomplished in the NASA LaRC AIRLAB facility using a DEC VAX-11 to interface with eight Bendix BDX 930 flight control processors. The interface software which provides this SIFT program development capability was developed by AIRLAB personnel. This technical memorandum describes the application and design of this software in detail, and is intended to assist both the user in performance of SIFT research and the systems programmer responsible for maintaining and/or upgrading the SIFT programming environment.

  7. Analysis SWT Bi-directional Adjustable Ejector%浅析SWT型双向可调式射流器

    Institute of Scientific and Technical Information of China (English)

    李祖才; 王剑波; 王剑平

    2000-01-01

    阐述SwT型双向可调式射流器的设计原理、结构、运行特点和使用价值。%The theory, structuer, operation performance and value of SWT bi-directional adjustable ejector are described in brief in this paper.

  8. An Observational Approach to Testing Bi-Directional Parent-Child Interactions as Influential to Child Eating and Weight

    Science.gov (United States)

    Demir, Defne; Skouteris, Helen; Dell'Aquila, Daniela; Aksan, Nazan; McCabe, Marita P.; Ricciardelli, Lina A.; Milgrom, Jeannette; Baur, Louise A.

    2012-01-01

    Obesity among children has been on the rise globally for the past few decades. Previous research has centred mainly on self/parent-reported measures examining only uni-directional parental feeding styles and practices. Recent discussions in the literature have raised the importance of bi-directional parent-child interactions in influencing…

  9. ROLE OF LEAF SURFACE WATER IN THE BI-DIRECTIONAL AMMONIA EXCHANGE BETWEEN THE ATMOSPHERE AND TERRESTRIAL BIOSPHERE

    Science.gov (United States)

    A field experiment was conducted to study the ammonia exchange between plants and the atmosphere in a soybean field in Duplin County, North Carolina during the summer of 2002. Measurements indicate that the net canopy-scale ammonia exchange is bi-directional and has a significant...

  10. Performance Analysis of Video PHY Controller Using Unidirection and Bi-directional IO Standard via 7 Series FPGA

    DEFF Research Database (Denmark)

    Das, Bhagwan; Abdullah, M F L; Hussain, Dil muhammed Akbar

    2017-01-01

    graphics consumes more power, this creates a need of designing the low power design for Video PHY controller. In this paper, the performance of Video PHY controller is analyzed by comparing the power consumption of unidirectional and bi-directional IO Standard over 7 series FPGA. It is determined...

  11. SEMICONDUCTOR INTEGRATED CIRCUITS: A self-adaptive full asynchronous bi-directional transmission channel for network-on-chips

    Science.gov (United States)

    Xuguang, Guan; Yintang, Yang; Zhangming, Zhu; Duan, Zhou

    2010-08-01

    To improve two shortcomings of conventional network-on-chips, i.e. low utilization rate in channels between routers and excessive interconnection lines, this paper proposes a full asynchronous self-adaptive bi-directional transmission channel. It can utilize interconnection lines and register resources with high efficiency, and dynamically detect the data transmission state between routers through a direction regulator, which controls the sequencer to automatically adjust the transmission direction of the bi-directional channel, so as to provide a flexible data transmission environment. Null convention logic units are used to make the circuit quasi-delay insensitive and highly robust. The proposed bi-directional transmission channel is implemented based on SMIC 0.18 μm standard CMOS technology. Post-layout simulation results demonstrate that this self-adaptive bi-directional channel has better performance on throughput, transmission flexibility and channel bandwidth utilization compared to a conventional single direction channel. Moreover, the proposed channel can save interconnection lines up to 30% and can provide twice the bandwidth resources of a single direction transmission channel. The proposed channel can apply to an on-chip network which has limited resources of registers and interconnection lines.

  12. Arginine bi-directional translocation and breakdown into ornithine along the arbuscular mycorrhizal mycelium

    Institute of Scientific and Technical Information of China (English)

    JIN HaiRu

    2009-01-01

    Bi-directional translocatlon and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycellum were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N-and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra-phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those In nitrate or exogenous Arg; however, glycerol supplied as an external car-bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio-synthesized In the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks.Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either In the mycorrhizal compartment or in the fungal compartment. Once Arg was translo-cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled In the fungal compartment, respectively. Evidently Orn formation indi-cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.

  13. Arginine bi-directional translocation and breakdown into ornithine along the arbuscular mycorrhizal mycelium

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Bi-directional translocation and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycelium were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N- and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra- phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those in nitrate or exogenous Arg; however, glycerol supplied as an external car- bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio- synthesized in the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks. Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either in the mycorrhizal compartment or in the fungal compartment. Once Arg was translo- cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled in the fungal compartment, respectively. Evidently Orn formation indi- cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.

  14. Shape Optimization of the Assisted Bi-directional Glenn surgery for stage-1 single ventricle palliation

    Science.gov (United States)

    Verma, Aekaansh; Shang, Jessica; Esmaily-Moghadam, Mahdi; Wong, Kwai; Marsden, Alison

    2016-11-01

    Babies born with a single functional ventricle typically undergo three open-heart surgeries starting as neonates. The first of these stages (BT shunt or Norwood) has the highest mortality rates of the three, approaching 30%. Proceeding directly to a stage-2 Glenn surgery has historically demonstrated inadequate pulmonary flow (PF) & high mortality. Recently, the Assisted Bi-directional Glenn (ABG) was proposed as a promising means to achieve a stable physiology by assisting the PF via an 'ejector pump' from the systemic circulation. We present preliminary parametrization and optimization results for the ABG geometry, with the goal of increasing PF. To limit excessive pressure increases in the Superior Vena Cava (SVC), the SVC pressure is included as a constraint. We use 3-D finite element flow simulations coupled with a single ventricle lumped parameter network to evaluate PF & the pressure constraint. We employ a derivative free optimization method- the Surrogate Management Framework, in conjunction with the OpenDIEL framework to simulate multiple simultaneous evaluations. Results show that nozzle diameter is the most important design parameter affecting ABG performance. The application of these results to patient specific situations will be discussed. This work was supported by an NSF CAREER award (OCI1150184) and by the XSEDE National Computing Resource.

  15. Bi-directional Exchange: the Cornerstone of Globally Focused Social Work.

    Science.gov (United States)

    Parker, Gary; Ali, Samira; Ringell, Kassia; McKay, Mary

    2014-03-01

    Social work holds a unique place relative to other professions in that it prioritizes the elimination of human suffering as its primary goal. The roots of the profession are firmly planted in Western theories, historically and culturally specific perspectives, and knowledge. History has repeatedly demonstrated an association between the arrival of Westerners and the subsequent control of natural resources. Some argue that the development of global social work practice has serious pitfalls, including diverting needed resources away from local contexts and inadvertently spreading western world-views, paradigms and practices. However, the social work profession is uniquely positioned to offer expertise and collaborate with those experiencing the serious consequences of social inequity and the dearth of economic and social resources locally and across the globe. Grounded in anti-oppressive theory, guided by the difficult, yet acute awareness of western privilege and racism, and drawing from social/collective action and collaborative paradigms, a bi-directional exchange and action are detailed as the foundations for globally focused social work. The skills and knowledge base for global social work are essential as populations locally and worldwide are impacted by a global economic system that innately increases serious social inequity. Comprehensive training and preparation for globally focused social work, critical to successful engagement in global practice are outlined.

  16. Possible bi-directional link between ETA receptors and protein kinase C in rat blood vessels

    Directory of Open Access Journals (Sweden)

    A. M. Northover

    1995-01-01

    Full Text Available Possible links have been investigated between activation of protein kinase C (PKC and endothelin (ET production by small blood vessels. Perfusion pressures were recorded from rat isolated mesenteric artery, with or without the small intestine attached, before and after addition to the perfusate of either ET-1, ET-3 or the PKC activator 12-deoxyphorbol 13-phenylacetate (DOPPA. Rises in perfusion pressure in response to ET-1 (10−8 Mor DOPPA (10−6 M were reduced significantly by pre-treatment with either the ETA receptor antagonist PD151242 (10−6 M or the PKC inhibitor Ro 31-8220 (10−6 M. ET-3 (10−8 M had a significant, albeit small, effect only when the gut was still attached to the mesentery. Inthis latter preparation ET-1 and DOPPA increased the permeability of villi microvessels to colloidal carbon in the perfusate. This effect of DOPPA was reduced by pre-treatment with either PD151242 or Ro 31-8220, but the effects of ET-1 were reduced significantly only by Ro 31-8220. ET-3 (10−8 M was without effect. The results suggest a possible bi-directional link between ETA receptors and PKC in the intestinal vasculature.

  17. Bi-directional modulation of AMPA receptor unitary conductance by synaptic activity

    Directory of Open Access Journals (Sweden)

    Matthews Paul

    2004-11-01

    Full Text Available Abstract Background Knowledge of how synapses alter their efficiency of communication is central to the understanding of learning and memory. The most extensively studied forms of synaptic plasticity are long-term potentiation (LTP and its counterpart long-term depression (LTD of AMPA receptor-mediated synaptic transmission. In the CA1 region of the hippocampus, it has been shown that LTP often involves a rapid increase in the unitary conductance of AMPA receptor channels. However, LTP can also occur in the absence of any alteration in AMPA receptor unitary conductance. In the present study we have used whole-cell dendritic recording, failures analysis and non-stationary fluctuation analysis to investigate the mechanism of depotentiation of LTP. Results We find that when LTP involves an increase in unitary conductance, subsequent depotentiation invariably involves the return of unitary conductance to pre-LTP values. In contrast, when LTP does not involve a change in unitary conductance then depotentiation also occurs in the absence of any change in unitary conductance, indicating a reduction in the number of activated receptors as the most likely mechanism. Conclusions These data show that unitary conductance can be bi-directionally modified by synaptic activity. Furthermore, there are at least two distinct mechanisms to restore synaptic strength from a potentiated state, which depend upon the mechanism of the previous potentiation.

  18. Operational characteristics of mixed traffic flow under bi-directional environment using cellular automaton

    Directory of Open Access Journals (Sweden)

    Zhenke Luo

    2014-12-01

    Full Text Available Mixed traffic flow composed of autos and non-autos widely exists in developing countries and areas. To investigate the operational characteristics of the mixed traffic flow consisting of vehicles in different types (large vehicles, cas, and bicycles, we develop a cellular automaton model to replicate the travel behaviors on a bi-directional road segment with respect to the physical and mechanic ftures of différent vehicle types. By implementing the eesential parameters calibrated through the field data collection, a numerical study is carried out considering the variation in volume, density, and velocity with different compositions of mixed traffic flows. The primary findings include: the average velocity of traffic flow and total volume decrease 60% and 30% after incorporating 10% bicycles, respectively; the phenomenon of double-summit in terms of the total volume appears when the proportion of bicycle is beyond 60%; the maximal total volume starts to recover when the proportion of bicycle is higher than 10 %.

  19. Current understanding of the bi-directional relationship of major depression with inflammation

    Directory of Open Access Journals (Sweden)

    Messay Berhane

    2012-02-01

    Full Text Available Abstract Consistent evidence links major depression and its affective components to negative health outcomes. Although the pathways of these effects are likely complex and multifactorial, recent evidence suggests that innate inflammatory processes may play a role. An overview of current literature suggests that pathways between negative moods and inflammation are bi-directional. Indeed, negative moods activate peripheral physiologic mechanisms that result in an up regulation of systemic levels of inflammation. Conversely, peripheral inflammatory mediators signal the brain to affect behavioral, affective and cognitive changes that are consistent with symptoms of major depressive disorder. It is likely that these pathways are part of a complex feedback loop that involves the nervous, endocrine, and immune systems and plays a role in the modulation of peripheral inflammatory responses to central and peripheral stimuli, in central responses to peripheral immune activation and in the maintenance of homeostatic balance. Further research is warranted to fully understand the role of central processes in this feedback loop, which likely contributes to the pathophysiology of mental and physical health.

  20. Synthesis and Analysis of Custom Bi-directional Reflectivity Distribution Functions in DIRSIG

    Science.gov (United States)

    Dank, J.; Allen, D.

    2016-09-01

    The bi-directional reflectivity distribution (BRDF) function is a fundamental optical property of materials, characterizing important properties of light scattered by a surface. For accurate radiance calculations using synthetic targets and numerical simulations such as the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model, fidelity of the target BRDFs is critical. While fits to measured BRDF data can be used in DIRSIG, obtaining high-quality data over a large spectral continuum can be time-consuming and expensive, requiring significant investment in illumination sources, sensors, and other specialized hardware. As a consequence, numerous parametric BRDF models are available to approximate actual behavior; but these all have shortcomings. Further, DIRSIG doesn't allow direct visualization of BRDFs, making it difficult for the user to understand the numerical impact of various models. Here, we discuss the innovative use of "mixture maps" to synthesize custom BRDFs as linear combinations of parametric models and measured data. We also show how DIRSIG's interactive mode can be used to visualize and analyze both available parametric models currently used in DIRSIG and custom BRDFs developed using our methods.

  1. Upgrade of a transverse ventilation system in a bi-directional tunnel

    Directory of Open Access Journals (Sweden)

    Vidmar Peter

    2012-01-01

    Full Text Available The Karavanke tunnel forms an important link between Slovenia and Austria. The almost 8 km long tunnel is operated with bi-directional traffic and does not have dedicated escape routes. Moreover, the ventilation in case of fire does not satisfy requirements of the EU Directive 2004/54/EC that specifies the minimum requirements for tunnels in the trans-European road network. The paper present results of the research conducted regarding the possibility of upgrade the existing system in order to reach the required level of safety at lower costs possible. It is shown that with simple but novel adaptations of the ventilation system, a sizeable increase in the overall level of safety can be achieved. The methodology applied is a combination of a simple pipe model for tunnel ventilation and for detailed fluid dynamics analysis the CFD model is used. The existing ventilation system that in fire ventilation extracts smoke from a single duct is replaced with the smoke extraction from both ducts applying four axial fans. The analysis is focused on air/smoke flow through the vents and ducts and on pressure drops calculated over the length of the ventilation duct and its influence on the total flow. The change of the flow condition also has influence on ventilation fan operation point that is investigated in the paper as well.

  2. Low frequency radio observations of bi-directional electron beams in the solar corona

    CERN Document Server

    Carley, Eoin P; Vilmer, Nicole; Gallagher, Peter T

    2015-01-01

    The radio signature of a shock travelling through the solar corona is known as a type II solar radio burst. In rare cases these bursts can exhibit a fine structure known as `herringbones', which are a direct indicator of particle acceleration occurring at the shock front. However, few studies have been performed on herringbones and the details of the underlying particle acceleration processes are unknown. Here, we use an image processing technique known as the Hough transform to statistically analyse the herringbone fine structure in a radio burst at $\\sim$20-90 MHz observed from the Rosse Solar-Terrestrial Observatory on 2011 September 22. We identify 188 individual bursts which are signatures of bi-directional electron beams continuously accelerated to speeds of 0.16$_{-0.10}^{+0.11} c$. This occurs at a shock acceleration site initially at a constant altitude of $\\sim$0.6 R$_{\\odot}$ in the corona, followed by a shift to $\\sim$0.5 R$_{\\odot}$. The anti-sunward beams travel a distance of 170$_{-97}^{+174}$ ...

  3. 4x10Gb/s WDM Bi-directional Gating in a Semiconductor Optical Amplifier by Using Polarization Multiplexing Technique

    DEFF Research Database (Denmark)

    Yu, Jianjun; Jeppesen, Palle

    2000-01-01

    Bi-directional SOA gating can further reduce the number of gating elements in the space switch, we demonstrate that a conventional SOA employing polarization multiplexing technique (PMT) can be used for bi-directional WDM gating operation at 10Gb/s....

  4. Review and parameterisation of bi-directional ammonia exchange between vegetation and the atmosphere

    Directory of Open Access Journals (Sweden)

    R.-S. Massad

    2010-11-01

    Full Text Available Current deposition schemes used in atmospheric chemical transport models do not generally account for bi-directional exchange of ammonia (NH3. Bi-directional exchange schemes, which have so far been applied at the plot scale, can be included in transport models, but need to be parameterised with appropriate values of the ground layer compensation point (χg, stomatal compensation point (χs and cuticular resistance (Rw. We review existing measurements of χg, χs as well as Rw and compile a comprehensive dataset from which we then propose generalised parameterisations. χs is related to Γs, the non-dimensional ratio of [NH4+]apo and [H+]apo in the apoplast, through the temperature dependence of the combined Henry and dissociation equilibrium. The meta-analysis suggests that the nitrogen (N input is the main driver of the apoplastic and bulk leaf concentrations of ammonium (NH4 apo, NH4 bulk. For managed ecosystems, the main source of N is fertilisation which is reflected in a peak value of χs a few days following application, but also alters seasonal values of NH4 apo and NH4 bulk. We propose a parameterisation for χs which includes peak values as a function of amount and type of fertiliser application which gradually decreases to a background value. The background χs is based on total N input to the ecosystem as a yearly fertiliser application and N deposition (Ndep. For non-managed ecosystems, χs is parameterised based solely on the link with Ndep.

    For Rw we propose a general parameterisation as a function of atmospheric relative humidity (RH, incorporating a minimum value (

  5. Review and parameterisation of bi-directional ammonia exchange between vegetation and the atmosphere

    Directory of Open Access Journals (Sweden)

    R.-S. Massad

    2010-04-01

    Full Text Available Current deposition schemes used in atmospheric chemical transport models do not generally account for bi-directional exchange of ammonia (NH3. Bi-directional exchange schemes, which have so far been applied at the plot scale, can be included in transport models, but need to be parameterised with appropriate values of the stomatal compensation point (χs and cuticular resistance (Rw. We here review existing measurements of χs as well as Rw and compile a comprehensive dataset from which we then propose generalised parameterisations. χs is related to Γs, the non-dimensional ratio of [NH4+]apo and [H+]apo in the apoplast, through the temperature dependence of the combined Henry and solubility equilibrium. The meta-analysis suggests that the nitrogen (N input is the main driver of the apoplastic and bulk leaf concentrations of ammonium (NH+4 apo, NH+4 bulk. For managed ecosystems, the main source of N is fertilisation which is reflected in a peak value of χs a few days following application, but also alters seasonal values of NH+4 apo and NH+4 bulk. We propose a parameterisation for χs which includes peak values as a function of amount and type of fertiliser application which gradually decreases to a background value. The background χs is set based on total N input to the ecosystem as a yearly fertiliser application and N deposition (Ndep. For non-managed ecosystems, χs is parameterised based solely on the link with Ndep.

    For Rw we propose a general parameterisation as a function of atmospheric Relative Humidity (RH, incorporating a minimum value (R w(min, which depends on the ratio of atmospheric acid

  6. No evidence for a functional role of bi-directional Notch signaling during angiogenesis.

    Directory of Open Access Journals (Sweden)

    Sven S Liebler

    Full Text Available The Delta-Notch pathway is a signal exchanger between adjacent cells to regulate numerous differentiation steps during embryonic development. Blood vessel formation by sprouting angiogenesis requires high expression of the Notch ligand DLL4 in the leading tip cell, while Notch receptors in the trailing stalk cells are activated by DLL4 to achieve strong Notch signaling activity. Upon ligand binding, Notch receptors are cleaved by ADAM proteases and gamma-secretase. This releases the intracellular Notch domain that acts as a transcription factor. There is evidence that also Notch ligands (DLL1, DLL4, JAG1, JAG2 are processed upon receptor binding to influence transcription in the ligand-expressing cell. Thus, the existence of bi-directional Delta-Notch signaling has been proposed. We report here that the Notch ligands DLL1 and JAG1 are processed in endothelial cells in a gamma-secretase-dependent manner and that the intracellular ligand domains accumulate in the cell nucleus. Overexpression of JAG1 intracellular domain (ICD as well as DLL1-ICD, DLL4-ICD and NOTCH1-ICD inhibited endothelial proliferation. Whereas NOTCH1-ICD strongly repressed endothelial migration and sprouting angiogenesis, JAG1-ICD, DLL1-ICD and DLL4-ICD had no significant effects. Consistently, global gene expression patterns were only marginally affected by the processed Notch ligands. In addition to its effects as a transcription factor, NOTCH1-ICD promotes cell adhesion to the extracellular matrix in a transcription-independent manner. However, JAG1-ICD, DLL1-ICD and DLL4-ICD did not influence endothelial cell adhesion. In summary, reverse signaling of Notch ligands appears to be dispensable for angiogenesis in cellular systems.

  7. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_TRMM-PFM_Edition1)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2000-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  8. Bi-Directional Tuning of Amygdala Sensitivity in Combat Veterans Investigated with fMRI.

    Directory of Open Access Journals (Sweden)

    Tom Brashers-Krug

    Full Text Available Combat stress can be followed by persistent emotional consequences. It is thought that these emotional consequences are caused in part by increased amygdala reactivity. It is also thought that amygdala hyper-reactivity results from decreased inhibition from portions of the anterior cingulate cortex (ACC in which activity is negatively correlated with activity in the amygdala. However, experimental support for these proposals has been inconsistent.We showed movies of combat and civilian scenes during a functional magnetic resonance imaging (fMRI session to 50 veterans of recent combat. We collected skin conductance responses (SCRs as measures of emotional arousal. We examined the relation of blood oxygenation-level dependent (BOLD signal in the amygdala and ACC to symptom measures and to SCRs.Emotional arousal, as measured with SCR, was greater during the combat movie than during the civilian movie and did not depend on symptom severity. As expected, amygdala signal during the less-arousing movie increased with increasing symptom severity. Surprisingly, during the more-arousing movie amygdala signal decreased with increasing symptom severity. These differences led to the unexpected result that amygdala signal in highly symptomatic subjects was lower during the more-arousing movie than during the less-arousing movie. Also unexpectedly, we found no significant inverse correlation between any portions of the amygdala and ACC. Rather, signal throughout more than 80% of the ACC showed a strong positive correlation with signal throughout more than 90% of the amygdala.Amygdala reactivity can be tuned bi-directionally, either up or down, in the same person depending on the stimulus and the degree of post-traumatic symptoms. The exclusively positive correlations in BOLD activity between the amygdala and ACC contrast with findings that have been cited as evidence for inhibitory control of the amygdala by the ACC. The conceptualization of post

  9. High accuracy solution of bi-directional wave propagation in continuum mechanics

    Science.gov (United States)

    Mulloth, Akhil; Sawant, Nilesh; Haider, Ijlal; Sharma, Nidhi; Sengupta, Tapan K.

    2015-10-01

    Solution of partial differential equations by numerical method is strongly affected due to numerical errors, which are caused mainly by deviation of numerical dispersion relation from the physical dispersion relation. To quantify and control such errors and obtain high accuracy solutions, we consider a class of problems which involve second derivative of unknowns with respect to time. Here, we analyse numerical metrics such as the numerical group velocity, numerical phase speed and the numerical amplification factor for different methods in solving the model bi-directional wave equation (BDWE). Such equations can be solved directly, for example, by Runge-Kutta-Nyström (RKN) method. Alternatively, the governing equation can be converted to a set of first order in time equations and then using four-stage fourth order Runge-Kutta (RK4) method for time integration. Spatial discretisation considered are the classical second and fourth order central difference schemes, along with Lele's central compact scheme for evaluating second derivatives. In another version, we have used Lele's scheme for evaluating first derivatives twice to obtain the second derivative. As BDWE represents non-dissipative, non-dispersive dynamics, we also consider the canonical problem of linearised rotating shallow water equation (LRSWE) in a new formulation involving second order derivative in time, which represents dispersive waves along with a stationary mode. The computations of LRSWE with RK4 and RKN methods for temporal discretisation and Lele's compact schemes for spatial discretisation are compared with computations performed with RK4 method for time discretisation and staggered compact scheme (SCS) for spatial discretisation by treating it as a set of three equations as reported in Rajpoot et al. (2012) [1].

  10. Steady-state analysis of the integrated natural gas and electric power system with bi-directional energy conversion

    DEFF Research Database (Denmark)

    Zeng, Qing; Fang, Jiakun; Li, Jinghua

    2016-01-01

    Nowadays, the electric power system and natural gas network are becoming increasingly coupled and interdependent. A harmonized integration of natural gas and electricity network with bi-directional energy conversion is expected to accommodate high penetration levels of renewables in terms of system...... flexibility. This work focuses on the steady-state analysis of the integrated natural gas and electric power system with bi-directional energy conversion. A unified energy flow formulation is developed to describe the nodal balance and branch flow in both systems and it is solved with the Newton...... series of wind power and power load are used to investigate the mitigation effect of the integrated energy system. At last, the effect of wind power and power demand on the output of Power to Gas (P2G) and gas-fired power generation (GPG) has also been investigated....

  11. A bi-directional DC/DC converter for hybrid wind generator/battery system with state machine control

    Energy Technology Data Exchange (ETDEWEB)

    Hua, C.C.; Liao, Y.C. [National Yunlin Univ. of Science and Technology, Yunlin, Taiwan (China). Dept. of Electrical Engineering

    2008-07-01

    A bi-directional DC to DC converter used in a hybrid wind generator/lead-acid battery power system was presented. A state machine control strategy was used to control both the system power flow and load distribution. It was also used to increase the power capacity of the system. The battery was also charged or discharged through the bi-directional DC to DC converter. Multi-stage current charging control of the batteries was accomplished by adjusting the duty cycle of the power converter. This also improved the charging efficiency by the maximum power point tracking algorithm. It was concluded that the proposed control method can be readily extended to other renewable energy conversion systems. 6 refs., 13 figs.

  12. Rapid multi-modality preregistration based on SIFT descriptor.

    Science.gov (United States)

    Chen, Jian; Tian, Jie

    2006-01-01

    This paper describes the scale invariant feature transform (SIFT) method for rapid preregistration of medical image. This technique originates from Lowe's method wherein preregistration is achieved by matching the corresponding keypoints between two images. The computational complexity has been reduced when we applied SIFT preregistration method before refined registration due to its O(n) exponential calculations. The features of SIFT are highly distinctive and invariant to image scaling and rotation, and partially invariant to change in illumination and contrast, it is robust and repeatable for cursorily matching two images. We also altered the descriptor so our method can deal with multimodality preregistration.

  13. Gender Recognition Based on Sift Features

    CERN Document Server

    Yousefi, Sahar

    2011-01-01

    This paper proposes a robust approach for face detection and gender classification in color images. Previous researches about gender recognition suppose an expensive computational and time-consuming pre-processing step in order to alignment in which face images are aligned so that facial landmarks like eyes, nose, lips, chin are placed in uniform locations in image. In this paper, a novel technique based on mathematical analysis is represented in three stages that eliminates alignment step. First, a new color based face detection method is represented with a better result and more robustness in complex backgrounds. Next, the features which are invariant to affine transformations are extracted from each face using scale invariant feature transform (SIFT) method. To evaluate the performance of the proposed algorithm, experiments have been conducted by employing a SVM classifier on a database of face images which contains 500 images from distinct people with equal ratio of male and female.

  14. Phosphorus reduction by sifting fish waste meal

    Directory of Open Access Journals (Sweden)

    Ronaldo Lima de Lima

    2014-10-01

    Full Text Available Fish meal is widely included in animal feed because it contains ideal essential amino acids profile, it is rich in energy, essential fatty acids, vitamins and minerals and with >80% apparent protein digestibility in peneid shrimp. In human nutrition, studies are investigating the inclusion of fish meal in snacks, cakes, breads and cookies, as an enrichment in calcium, phosphorus, iron, protein and, especially, omega-3 fatty acids. Omega-3 fatty acids reduces heart diseases and have antithrombotic and anti-inflammatory properties (eicosapentaenoic acid, and are essential to the formation of brain tissue and retina in infants and are important during pregnancy and lactation (docosahexaenoic acid. Fish meal produced from fish waste is rich in minerals (phosphorus, which may cause eutrophication and impair water quality in aquaculture. The aim of this study was to reduce phosphorus content from commercial fish meal produced from waste by sifting (0.60 - 1.00 - 1.18 - 1.40 - 2.36 and 3.35mm mesh sizes. Fish meal samples were collected monthly for 24 months. Proximate composition of subsamples per mesh size was compared to the unsieved sample. Results indicate that sifting through a 0.60mm sieve total phosphorus and ash contents were reduced up to 32% and 36%, respectively, further to increase protein content up to 20%. Average composition of the subsamples was 47.04% ash, 5.56% of total phosphorus and 39.45% protein, suggesting that the residue of the fractionation may be marketed as a mineral and protein supplement.

  15. Evaluation of Sift and Surf for Vision Based Localization

    Science.gov (United States)

    Qu, Xiaozhi; Soheilian, Bahman; Habets, Emmanuel; Paparoditis, Nicolas

    2016-06-01

    Vision based localization is widely investigated for the autonomous navigation and robotics. One of the basic steps of vision based localization is the extraction of interest points in images that are captured by the embedded camera. In this paper, SIFT and SURF extractors were chosen to evaluate their performance in localization. Four street view image sequences captured by a mobile mapping system, were used for the evaluation and both SIFT and SURF were tested on different image scales. Besides, the impact of the interest point distribution was also studied. We evaluated the performances from for aspects: repeatability, precision, accuracy and runtime. The local bundle adjustment method was applied to refine the pose parameters and the 3D coordinates of tie points. According to the results of our experiments, SIFT was more reliable than SURF. Apart from this, both the accuracy and the efficiency of localization can be improved if the distribution of feature points are well constrained for SIFT.

  16. Face Identification by SIFT-based Complete Graph Topology

    CERN Document Server

    Kisku, Dakshina Ranjan; Grosso, Enrico; Tistarelli, Massimo

    2010-01-01

    This paper presents a new face identification system based on Graph Matching Technique on SIFT features extracted from face images. Although SIFT features have been successfully used for general object detection and recognition, only recently they were applied to face recognition. This paper further investigates the performance of identification techniques based on Graph matching topology drawn on SIFT features which are invariant to rotation, scaling and translation. Face projections on images, represented by a graph, can be matched onto new images by maximizing a similarity function taking into account spatial distortions and the similarities of the local features. Two graph based matching techniques have been investigated to deal with false pair assignment and reducing the number of features to find the optimal feature set between database and query face SIFT features. The experimental results, performed on the BANCA database, demonstrate the effectiveness of the proposed system for automatic face identifi...

  17. KW-SIFT descriptor for remote-sensing image registration

    Institute of Scientific and Technical Information of China (English)

    Xiangzeng Liu; Zheng Tian; Weidong Yan; Xifa Duan

    2011-01-01

    A technique to construct an affine invariant descriptor for remote-sensing image registration based on the scale invariant features transform (SIFT) in a kernel space is proposed.Affine invariant SIFT descriptor is first developed in an elliptical region determined by the Hessian matrix of the feature points.Thereafter,the descriptor is mapped to a feature space induced by a kernel, and a new descriptor is constructed by whitening the mapped descriptor in the feature space, with the transform called KW-SIFT.In a final step, the new descriptor is used to register remote-sensing images.Experimental results for remote-sensing image registration indicate that the proposed method improves the registration performance as compared with other related methods.%@@ A technique to construct an affine invariant descriptor for remote-sensing image registration based on the scale invariant features transform (SIFT) in a kernel space is proposed.Affine invariant SIFT descriptor is first developed in an elliptical region determined by the Hessian matrix of the feature points.Thereafter,the descriptor is mapped to a feature space induced by a kernel, and a new descriptor is constructed by whitening the mapped descriptor in the feature space, with the transform called KW-SIFT.In a final step, the new descriptor is used to register remote-sensing images.Experimental results for remote-sensing image registration indicate that the proposed method improves the registration performance as compared with other related methods.

  18. Synchronization of Chaotic Storage-Ring Free-Electron Laser by Bi-Directional Coupling Scheme with the Coupling Strength Varied Periodically

    Institute of Scientific and Technical Information of China (English)

    HUANG Liang-Yu; LUO Xiao-Shu

    2006-01-01

    @@ We analyse the chaotic dynamics of storage-ring free-electron lasers and report a bi-directional coupled scheme with the coupling strength varied periodically to synchronize two chaotic storage-ring free-electron lasers.

  19. Laboratory characterization of a CCD camera system for retrieval of bi-directional reflectance distribution function

    Science.gov (United States)

    Nandy, Prabal; Thome, Kurtis J.; Biggar, Stuart F.

    1999-12-01

    The Remote Sensing Group of the Optical Science Center at the University of Arizona has developed a four-band, multi- spectral, wide-angle, imaging radiometer for the retrieval of the bi-directional reflectance distribution function (BRDF) for vicarious calibration applications. The system consists of a fisheye lens with four interference filters centered at 470 nm, 575 nm, 660 nm, and 835 nm for spectral selection and an astronomical grade 1024 X 1024-pixel, silicon CCD array. Data taken by the system fit in the array as a nominally 0.2 degree per pixel image. This imaging radiometer system has been used in support of the calibration of Landsat-5 and SPOT- satellite sensors. This paper presents the results of laboratory characterization of the system to determine linearity of the detector, point spread function (PSF) and polarization effects. The linearity study was done on detector array without the lens, using a spherical-integrating source with a 1.5-mm aperture. This aperture simulates a point source for distances larger than 60 cm. Data were collected as both a function of exposure time and distance from the source. The results of these measurements indicate that each detector of the array is linear to better than 0.5%. Assuming a quadratic response improves this fit to better than 0.1% over 88% of the upper end of the detector's dynamic range. The point spread function (PSF) of the lens system was measured using the sphere source and aperture with the full camera system operated at a distance of 700 mm from the source, thus the aperture subtends less than the field of view of one pixel. The PSF was measured for several field angles and the signal level was found to fall to less than 1% of the peak signal within 1.5-degrees (10 pixels) for the on-axis case. The effect of this PSF on the retrieval of modeled BRDFs is shown to be less than 0.2% out to view angles of 70 degrees. The final test presented is one to assess the polarization effects of the lens

  20. User's guide to programming fault injection and data acquisition in the SIFT environment

    Science.gov (United States)

    Elks, Carl R.; Green, David F.; Palumbo, Daniel L.

    1987-01-01

    Described are the features, command language, and functional design of the SIFT (Software Implemented Fault Tolerance) fault injection and data acquisition interface software. The document is also intended to assist and guide the SIFT user in defining, developing, and executing SIFT fault injection experiments and the subsequent collection and reduction of that fault injection data. It is also intended to be used in conjunction with the SIFT User's Guide (NASA Technical Memorandum 86289) for reference to SIFT system commands, procedures and functions, and overall guidance in SIFT system programming.

  1. Evaluation of a regional air-quality model with bi-directional NH3 exchange coupled to an agro-ecosystem model

    Directory of Open Access Journals (Sweden)

    J. E. Pleim

    2012-08-01

    Full Text Available Atmospheric ammonia (NH3 is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH3 contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurements indicate that the air-surface exchange of NH3 is bi-directional. However, the effects of bi-directional exchange, soil biogeochemistry and human activity are not parameterized in air quality models. The US Environmental Protection Agency (EPA's Community Multiscale Air-Quality (CMAQ model with bi-directional NH3 exchange has been coupled with the United States Department of Agriculture (USDA's Environmental Policy Integrated Climate (EPIC agro-ecosystem model's nitrogen geochemistry algorithms. CMAQ with bi-directional NH3 exchange coupled to EPIC connects agricultural cropping management practices to emissions and atmospheric concentrations of reduced nitrogen and models the biogeochemical feedback on NH3 air-surface exchange. This coupled modeling system reduced the biases and error in NHx (NH3 + NH4+ wet deposition and in ambient aerosol concentrations in an annual 2002 Continental US (CONUS domain simulation when compared to a 2002 annual simulation of CMAQ without bi-directional exchange. Fertilizer emissions estimated in CMAQ 5.0 with bi-directional exchange exhibits markedly different seasonal dynamics than the US EPA's National Emissions Inventory (NEI, with lower emissions in the spring and fall and higher emissions in July.

  2. SIFT flow for large-displacement object tracking.

    Science.gov (United States)

    Zhang, Huanlong; Hu, Shiqiang; Zhang, Xiaoyu

    2014-09-20

    Traditional tracking methods place an emphasis on how to cope with the variations in target appearance effectively. However, when the motion displacement of the target between image frames becomes larger, these methods may be unstable. This paper presents a novel (to our knowledge) visual object tracking method. In this method, we first introduce scale-invariant feature transform (SIFT) flow into the tracking problem and develop a real-time motion prediction method to capture large displacement between consecutive image frames. Then we use belief propagation (BP) to convert the problem of finding maximum a posteriori probability (MAP) to globally minimizing an energy function to get the best matching pairs of points for producing good candidate regions of the target. And last, the refined point trajectories are obtained according to the bidirectional flow field consistency estimation and covariance region descriptor matching, which can update model states efficiently so as to achieve enhanced robustness for visual tracking. Compared with the state-of-art tracking methods, the experimental results demonstrate that the proposed algorithm shows favorable performance when the object undergoes large motion displacement between image frames.

  3. Impact and Use of the Asymmetric Property in Bi-directional Cooperative Relaying under Asymmetric Traffic Conditions

    Science.gov (United States)

    Saeki, Takaaki; Yamamoto, Koji; Murata, Hidekazu; Yoshida, Susumu

    Cooperative relaying (CR) is a promising technique to provide spatial diversity by combining multiple signals from source and relay stations. In the present paper, the impact and use of the asymmetric property in bi-directional CR under asymmetric traffic conditions are discussed assuming that CR involves one communication pair and one relay station in a time division duplex (TDD) system. The asymmetric property means that the average communication quality differs for each transmission direction because of the difference in signal power between the combined signals for each direction. First, numerical results show the asymmetric property of bi-directional CR. Next, in order to evaluate the impact of the asymmetric property, the optimal relay position and resource allocation are compared to those in simple multi-hop relaying, which does not have the asymmetric property. Numerical results show that, in order to maximize the overall quality of bi-directional communication, the optimal relay position in CR depends on the offered traffic ratio, which is defined as the traffic ratio of each transmission direction, while the offered traffic ratio does not affect the optimal relay position in multi-hop relaying. Finally, the asymmetric property is used to enhance the overall quality. Specifically, a high overall quality can be achieved by, for example, opportunistically switching to the transmission direction with higher quality. Under asymmetric traffic conditions, weighted proportionally fair scheduling (WPFS), which is proposed in the context of downlink scheduling in a cellular network, is applied to transmission direction switching. Numerical results reveal that WPFS provides a high overall quality and that the quality ratio is similar to the offered traffic ratio.

  4. Partial fingerprint matching based on SIFT Features

    Directory of Open Access Journals (Sweden)

    Ms. S.Malathi,

    2010-07-01

    Full Text Available Fingerprints are being extensively used for person identification in a number of commercial, civil, and forensic applications. The current Fingerprint matching technology is quite mature for matching full prints, matching partial fingerprints still needs lots of improvement. Most of the current fingerprint identification systems utilize features that are based on minutiae points and ridge patterns. The major challenges faced in partial fingerprint matching are the absence of sufficient minutiae features and other structures such as core and delta. However, this technology suffers from the problem of handling incomplete prints and often discards any partial fingerprints obtained. Recent research has begun to delve into the problems of latent or partial fingerprints. In this paper we present a novel approach for partial fingerprint matching scheme based on SIFT(Scale Invariant Feature Transform features and matching is achieved using a modified point matching process. Using Neurotechnology database, we demonstrate that the proposed method exhibits an improved performance when matching full print against partial print.

  5. Modified SIFT Descriptors for Face Recognition under Different Emotions

    Directory of Open Access Journals (Sweden)

    Nirvair Neeru

    2016-01-01

    Full Text Available The main goal of this work is to develop a fully automatic face recognition algorithm. Scale Invariant Feature Transform (SIFT has sparingly been used in face recognition. In this paper, a Modified SIFT (MSIFT approach has been proposed to enhance the recognition performance of SIFT. In this paper, the work is done in three steps. First, the smoothing of the image has been done using DWT. Second, the computational complexity of SIFT in descriptor calculation is reduced by subtracting average from each descriptor instead of normalization. Third, the algorithm is made automatic by using Coefficient of Correlation (CoC instead of using the distance ratio (which requires user interaction. The main achievement of this method is reduced database size, as it requires only neutral images to store instead of all the expressions of the same face image. The experiments are performed on the Japanese Female Facial Expression (JAFFE database, which indicates that the proposed approach achieves better performance than SIFT based methods. In addition, it shows robustness against various facial expressions.

  6. The effect of bi-directional loading on fatigue assessment of pressurized piping elbows with local thinned areas

    Energy Technology Data Exchange (ETDEWEB)

    Balan, C. [Department of Mechanical Engineering, Univeristy of Ottawa, Ottawa, Ont., KIN 6N5 (Canada); Redekop, D. [Department of Mechanical Engineering, Univeristy of Ottawa, Ottawa, Ont., KIN 6N5 (Canada)]. E-mail: dredekop@tesla.cc.uottawa.ca

    2005-03-01

    An elastic-plastic finite element study is conducted to determine the effect of bi-directional loading on the fatigue characteristics of pressurized 90 deg. piping elbows with local thinned areas. The analysis is conducted on pressurized piping elbows considered previously in the literature, but analyzed only for in-plane loading. Considering also the out-of-plane loading the present analysis seeks to simulate simultaneous horizontal and vertical seismic actions. A validation study is first conducted in which the present results obtained for in-plane loading are compared with previous results. Comparisons are made for deformation patterns, hoop strain histories, and reaction forces. The relative in-plane to out-of-plane load intensities to be adopted for the combined loading case is determined next. Results considering bi-directional loadings are then found for the pressurized piping elbow for a total of 23 cases of local area thinning. Finally conclusions are drawn about the significance of considering the additional out-of-plane loading.

  7. A high-damping magnetorheological elastomer with bi-directional magnetic-control modulus for potential application in seismology

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Miao, E-mail: yumiao@cqu.edu.cn; Qi, Song; Fu, Jie; Zhu, Mi [Key Lab for Optoelectronic Technology and Systems, Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)

    2015-09-14

    A high-damping magnetorheological elastomer (MRE) with bi-directional magnetic-control modulus is developed. This MRE was synthesized by filling NdFeB particles into polyurethane (PU)/ epoxy (EP) interpenetrating network (IPN) structure. The anisotropic samples were prepared in a permanent magnetic field and magnetized in an electromagnetic field of 1 T. Dynamic mechanical responses of the MRE to applied magnetic fields are investigated through magneto-rheometer, and morphology of MREs is observed via scanning electron microscope (SEM). Test result indicates that when the test field orientation is parallel to that of the sample's magnetization, the shear modulus of sample increases. On the other hand, when the orientation is opposite to that of the sample's magnetization, shear modulus decreases. In addition, this PU/EP IPN matrix based MRE has a high-damping property, with high loss factor and can be controlled by applying magnetic field. It is expected that the high damping property and the ability of bi-directional magnetic-control modulus of this MRE offer promising advantages in seismologic application.

  8. Cooperation of electrically stimulated muscle and pneumatic muscle to realize RUPERT bi-directional motion for grasping.

    Science.gov (United States)

    Xikai Tu; Jiping He; Yue Wen; Jian Huang; Xinhan Huang; Hailong Huang; Meng Guo; Yong Yuan

    2014-01-01

    Robot-assisted rehabilitation is an active area of research to meet the demand of repetitive therapy in stroke rehabilitation. Robotic upper-extremity repetitive trainer (RUPERT) with its unidirectional pneumatic muscle actuation (PMA) can be used by most stroke patients that have difficulty moving in one direction because of a weak agonist or hyperactive antagonist. In this research, to broaden the usage of RUPERT, we not only add grasping functionality to the rehabilitation robot with the help of surface Functional Electrical Stimulation (FES) but also realize the robot joint bi-directional motion by using a PMA in cooperation with surface FES evoked paralyzed muscle force. This integrative rehabilitation strategy is explored for training patients to practice coordinated reaching and grasping functions. The effectiveness of this FES electrically evoked bio-actuator way is verified through a method that separates the mixed electromyogram (MEMG) into the electrically evoked electromyogram (EEMG) and voluntary electromyogram (VEMG). This is a promising approach to alleviate the size and mechanical complexity of the robot, thereby the cost of the joint bi-directional actuator rehabilitation robot by means of their own characteristics of stroke subjects.

  9. 基于SIFT,PCA-SIFT和SURF特征检测方法的研究%Based on SIFT,PCA-SIFT and SURF Feature Detection Method Research

    Institute of Scientific and Technical Information of China (English)

    李宏荣; 李晓明

    2012-01-01

    To study features,we compared with SIFT(Scale Invariant Feature Transform),PCA-SIFT(Principal Component Analysis Scale Invariant Feature Transform)and SURF(Speeded Up Robust Features)three kinds of robust feature detection method.We use KNN(K-Nearest Neighbor)and random sampling method of these three kinds of methods for analysis.Where KNN used to seek matching pairs,random sampling for removing errors from match to match.Feature detection performance robustness is the image rotation,image blurring,illumination variation,the scale change of the image.The experimental evaluation is the use of repetition rate and the number of correct matching of the two statistical methods.In a variety of image transform in SIFT and SURF performance is consistent,but also has faster calculation speed.PCA-SIFT in the image rotation and illumination changes provides a better performance.%文章对SIFT,PCA-SIFT和SURF三种鲁棒性较强的特征检测方法作对比.文中运用KNN(K-Nearest Neighbor)和RANSAC的方法对这三种方法进行分析.其中KNN用于寻求匹配对,RANSAC用于从匹配对中剔除错误匹配.特征检测性能的鲁棒性主要是对图像旋转、图像模糊、光照变化、尺度变化下的图像进行测试.在各种图像变换中SIFT都体现出了稳定性,但计算速度相对比较慢.SURF不仅与SIFT的性能相一致,而且还拥有较快的计算速度.PCA-SIFT在图像旋转和光照变化中有较好的性能.

  10. Research on video target tracking technology based on improved SIFT algorithm

    Science.gov (United States)

    Zhuang, Zhemin; Guo, Zhijie; Yuang, Ye

    2017-01-01

    A novel target tracking algorithm based on improved SIFT (Scale Invariant Feature Transform (SIFT) algorithm is proposed in this paper. In order to improve real-time performance, the processing neighborhood of SIFT has been improved to decrease the complexity of calculation, and the dimension of the SIFT vector is set from 128 to 40. Simulations and experiments show this improved algorithm brings us low computation complexity and high tracking accuracy and robustness.

  11. A NEW OBJECT BASED QUALITY METRIC BASED ON SIFT AND SSIM

    OpenAIRE

    Decombas, Marc; Dufaux, Frederic; Renan, Erwann; Pesquet-Popescu, Beatrice; Capman, Francois

    2012-01-01

    ICIP2012; We propose a full reference visual quality metric to evaluate a semantic coding system which may not preserve exactly the position and/or the shape of objects. The metric is based on Scale-Invariant Feature Transform (SIFT) points. More specifically, Structural SIMilarity (SSIM) on windows around the SIFT points measures the compression artifacts (SSIM_SIFT). Conversely, the standard deviation of the matching distance between the SIFT points measures the geometric distortion (GEOMET...

  12. [Multiple transmission electron microscopic image stitching based on sift features].

    Science.gov (United States)

    Li, Mu; Lu, Yanmeng; Han, Shuaihu; Wu, Zhuobin; Chen, Jiajing; Liu, Zhexing; Cao, Lei

    2015-08-01

    We proposed a new stitching method based on sift features to obtain an enlarged view of transmission electron microscopic (TEM) images with a high resolution. The sift features were extracted from the images, which were then combined with fitted polynomial correction field to correct the images, followed by image alignment based on the sift features. The image seams at the junction were finally removed by Poisson image editing to achieve seamless stitching, which was validated on 60 local glomerular TEM images with an image alignment error of 62.5 to 187.5 nm. Compared with 3 other stitching methods, the proposed method could effectively reduce image deformation and avoid artifacts to facilitate renal biopsy pathological diagnosis.

  13. Fast SIFT design for real-time visual feature extraction.

    Science.gov (United States)

    Chiu, Liang-Chi; Chang, Tian-Sheuan; Chen, Jiun-Yen; Chang, Nelson Yen-Chung

    2013-08-01

    Visual feature extraction with scale invariant feature transform (SIFT) is widely used for object recognition. However, its real-time implementation suffers from long latency, heavy computation, and high memory storage because of its frame level computation with iterated Gaussian blur operations. Thus, this paper proposes a layer parallel SIFT (LPSIFT) with integral image, and its parallel hardware design with an on-the-fly feature extraction flow for real-time application needs. Compared with the original SIFT algorithm, the proposed approach reduces the computational amount by 90% and memory usage by 95%. The final implementation uses 580-K gate count with 90-nm CMOS technology, and offers 6000 feature points/frame for VGA images at 30 frames/s and ∼ 2000 feature points/frame for 1920 × 1080 images at 30 frames/s at the clock rate of 100 MHz.

  14. Progress in SIFT-MS: breath analysis and other applications.

    Science.gov (United States)

    Spaněl, Patrik; Smith, David

    2011-01-01

    The development of selected ion flow tube mass spectrometry, SIFT-MS, is described from its inception as the modified very large SIFT instruments used to demonstrate the feasibility of SIFT-MS as an analytical technique, towards the smaller but bulky transportable instruments and finally to the current smallest Profile 3 instruments that have been located in various places, including hospitals and schools to obtain on-line breath analyses. The essential physics and engineering principles are discussed, which must be appreciated to design and construct a SIFT-MS instrument. The versatility and sensitivity of the Profile 3 instrument is illustrated by typical mass spectra obtained using the three precursor ions H(3)O(+), NO(+) and O(2)(+)·, and the need to account for differential ionic diffusion and mass discrimination in the analytical algorithms is emphasized to obtain accurate trace gas analyses. The performance of the Profile 3 instrument is illustrated by the results of several pilot studies, including (i) on-line real time quantification of several breath metabolites for cohorts of healthy adults and children, which have provided representative concentration/population distributions, and the comparative analyses of breath exhaled via the mouth and nose that identify systemic and orally-generated compounds, (ii) the enhancement of breath metabolites by drug ingestion, (iii) the identification of HCN as a marker of Pseudomonas colonization of the airways and (iv) emission of volatile compounds from urine, especially ketone bodies, and from skin. Some very recent developments are discussed, including the quantification of carbon dioxide in breath and the combination of SIFT-MS with GC and ATD, and their significance. Finally, prospects for future SIFT-MS developments are alluded to.

  15. The SIFT hardware/software systems. Volume 2: Software listings

    Science.gov (United States)

    Palumbo, Daniel L.

    1985-01-01

    This document contains software listings of the SIFT operating system and application software. The software is coded for the most part in a variant of the Pascal language, Pascal*. Pascal* is a cross-compiler running on the VAX and Eclipse computers. The output of Pascal* is BDX-390 assembler code. When necessary, modules are written directly in BDX-390 assembler code. The listings in this document supplement the description of the SIFT system found in Volume 1 of this report, A Detailed Description.

  16. Image matching with an improved descriptor based on SIFT

    Science.gov (United States)

    Hu, Xuemei; Ding, Yan

    2017-01-01

    In this paper, we propose a novel 30-dimension descriptor named SIFTRO(SIFT of Ring Order) to promote the matching speed, which is generated from 3 local ring areas. A new element reordering method is presented to ensure the descriptor's rotation invariance. To obtain the best scale factor for SIFTRO descriptor, the weight hierarchy decision model based on AHP is designed. The experiments show that the SIFTRO descriptor inherits the advantages of the invariance to image scaling, rotation and affine, and it also speeds up greatly in image matching, while the precision is improved compared with that of original SIFT.

  17. Image mosaic method based on SIFT features of line segment.

    Science.gov (United States)

    Zhu, Jun; Ren, Mingwu

    2014-01-01

    This paper proposes a novel image mosaic method based on SIFT (Scale Invariant Feature Transform) feature of line segment, aiming to resolve incident scaling, rotation, changes in lighting condition, and so on between two images in the panoramic image mosaic process. This method firstly uses Harris corner detection operator to detect key points. Secondly, it constructs directed line segments, describes them with SIFT feature, and matches those directed segments to acquire rough point matching. Finally, Ransac method is used to eliminate wrong pairs in order to accomplish image mosaic. The results from experiment based on four pairs of images show that our method has strong robustness for resolution, lighting, rotation, and scaling.

  18. Automated Photogrammetric Image Matching with Sift Algorithm and Delaunay Triangulation

    DEFF Research Database (Denmark)

    Karagiannis, Georgios; Antón Castro, Francesc/François; Mioc, Darka

    2016-01-01

    An algorithm for image matching of multi-sensor and multi-temporal satellite images is developed. The method is based on the SIFT feature detector proposed by Lowe in (Lowe, 1999). First, SIFT feature points are detected independently in two images (reference and sensed image). The features...... of each feature set for each image are computed. The isomorphism of the Delaunay triangulations is determined to guarantee the quality of the image matching. The algorithm is implemented in Matlab and tested on World-View 2, SPOT6 and TerraSAR-X image patches....

  19. Improved Feature Detection in Fused Intensity-Range Images with Complex SIFT (ℂSIFT

    Directory of Open Access Journals (Sweden)

    Boris Jutzi

    2011-09-01

    Full Text Available The real and imaginary parts are proposed as an alternative to the usual Polar representation of complex-valued images. It is proven that the transformation from Polar to Cartesian representation contributes to decreased mutual information, and hence to greater distinctiveness. The Complex Scale-Invariant Feature Transform (ℂSIFT detects distinctive features in complex-valued images. An evaluation method for estimating the uniformity of feature distributions in complex-valued images derived from intensity-range images is proposed. In order to experimentally evaluate the proposed methodology on intensity-range images, three different kinds of active sensing systems were used: Range Imaging, Laser Scanning, and Structured Light Projection devices (PMD CamCube 2.0, Z+F IMAGER 5003, Microsoft Kinect.

  20. Topology optimization using bi-directional evolutionary structural optimization based on the element-free Galerkin method

    Science.gov (United States)

    Shobeiri, Vahid

    2016-03-01

    In this article, the bi-directional evolutionary structural optimization (BESO) method based on the element-free Galerkin (EFG) method is presented for topology optimization of continuum structures. The mathematical formulation of the topology optimization is developed considering the nodal strain energy as the design variable and the minimization of compliance as the objective function. The EFG method is used to derive the shape functions using the moving least squares approximation. The essential boundary conditions are enforced by the method of Lagrange multipliers. Several topology optimization problems are presented to show the effectiveness of the proposed method. Many issues related to topology optimization of continuum structures, such as chequerboard patterns and mesh dependency, are studied in the examples.

  1. Parallel input parallel output high voltage bi-directional converters for driving dielectric electro active polymer actuators

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.;

    2014-01-01

    is to design and implement driving circuits for the DEAP actuators for their use in various applications. This paper presents implementation of parallel input, parallel output, high voltage (~2.5 kV) bi-directional DC-DC converters for driving the DEAP actuators. The topology is a bidirectional flyback DC......-DC converter incorporating commercially available high voltage MOSFETs (4 kV) and high voltage diodes (5 kV). Although the average current of the aforementioned devices is limited to 300 mA and 150 mA, respectively, connecting the outputs of multiple converters in parallel can provide a scalable design....... This enables operating the DEAP actuators in various static and dynamic applications e.g. positioning, vibration generation or damping, and pumps. The proposed idea is experimentally verified by connecting three high voltage converters in parallel to operate a single DEAP actuator. The experimental results...

  2. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications

    Directory of Open Access Journals (Sweden)

    Seung-Hyun Eom

    2015-12-01

    Full Text Available In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT switch and a balun element. A double-sided parallel-strip line (DSPSL is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch.

  3. Skills Inventory for Teams (SIFT): A Resource for Teams.

    Science.gov (United States)

    Garland, Corinne; And Others

    The Skills Inventory for Teams (SIFT) was developed for early intervention practitioners from a variety of disciplines to help them evaluate their ability to work as part of an early intervention team in identifying and serving young children with disabilities. The Team Member section is designed to help individual team members identify the skills…

  4. Novel averaging window filter for SIFT in infrared face recognition

    Institute of Scientific and Technical Information of China (English)

    Junfeng Bai; Yong Ma; Jing Li; Fan Fan; Hongyuan Wang

    2011-01-01

    The extraction of stable local features directly affects the performance of infrared face recognition algorithms. Recent studies on the application of scale invariant feature transform (SIFT) to infrared face recognition show that star-styled window filter (SWF) can filter out errors incorrectly introduced by SIFT. The current letter proposes an improved filter pattern called Y-styled window filter (YWF) to further eliminate the wrong matches. Compared with SWF, YWF patterns are sparser and do not maintain rotation invariance; thus, they are more suitable to infrared face recognition. Our experimental results demonstrate that a YWF-based averaging window outperforms an SWF-based one in reducing wrong matches, therefore improving the reliability of infrared face recognition systems.%@@ The extraction of stable local features directly affects the performance of infrared face recognition algorithms.Recent studies on the application of scale invariant feature transform(SIFT) to infrared face recognition show that star-styled window filter(SWF) can filter out errors incorrectly introduced by SIFT.

  5. Causal relationship between obesity and vitamin D status: bi-directional Mendelian randomization analysis of multiple cohorts.

    Directory of Open Access Journals (Sweden)

    Karani S Vimaleswaran

    Full Text Available Obesity is associated with vitamin D deficiency, and both are areas of active public health concern. We explored the causality and direction of the relationship between body mass index (BMI and 25-hydroxyvitamin D [25(OHD] using genetic markers as instrumental variables (IVs in bi-directional Mendelian randomization (MR analysis.We used information from 21 adult cohorts (up to 42,024 participants with 12 BMI-related SNPs (combined in an allelic score to produce an instrument for BMI and four SNPs associated with 25(OHD (combined in two allelic scores, separately for genes encoding its synthesis or metabolism as an instrument for vitamin D. Regression estimates for the IVs (allele scores were generated within-study and pooled by meta-analysis to generate summary effects. Associations between vitamin D scores and BMI were confirmed in the Genetic Investigation of Anthropometric Traits (GIANT consortium (n = 123,864. Each 1 kg/m(2 higher BMI was associated with 1.15% lower 25(OHD (p = 6.52×10⁻²⁷. The BMI allele score was associated both with BMI (p = 6.30×10⁻⁶² and 25(OHD (-0.06% [95% CI -0.10 to -0.02], p = 0.004 in the cohorts that underwent meta-analysis. The two vitamin D allele scores were strongly associated with 25(OHD (p≤8.07×10⁻⁵⁷ for both scores but not with BMI (synthesis score, p = 0.88; metabolism score, p = 0.08 in the meta-analysis. A 10% higher genetically instrumented BMI was associated with 4.2% lower 25(OHD concentrations (IV ratio: -4.2 [95% CI -7.1 to -1.3], p = 0.005. No association was seen for genetically instrumented 25(OHD with BMI, a finding that was confirmed using data from the GIANT consortium (p≥0.57 for both vitamin D scores.On the basis of a bi-directional genetic approach that limits confounding, our study suggests that a higher BMI leads to lower 25(OHD, while any effects of lower 25(OHD increasing BMI are likely to be small. Population level interventions to

  6. SIFT Feature Matching Algorithm with Local Shape Context

    Directory of Open Access Journals (Sweden)

    Gu Lichuan

    2013-05-01

    Full Text Available SIFT (Scale Invariant Feature Transform is one of the most effective local feature of scale, rotation and illumination invariant, which is widely used in the field of image matching. While there will be a lot mismatches when an image has many similar regions. In this study, an improved SIFT feature matching algorithm with local shape context is put forward. The feature vectors are computed by dominant orientation assignment to each feature point based on elliptical neighboring region and with local shape context and then the feature vectors are matched by using Euclidean distance and the X2 distance. The experiment indicates that the improved algorithm can reduce mismatch probability and acquire good performance on affine invariance, improves matching results greatly.

  7. Topological coding and its application in the refinement of SIFT.

    Science.gov (United States)

    Liu, Run Zong; Tang, Yuan Yan; Fang, Bin

    2014-11-01

    Point pattern matching plays a prominent role in the fields of computer vision and pattern recognition. A technique combining the circular onion peeling and the radial decomposition is proposed to analyze the topology structure of a point pattern. The analysis derives a feature which records the topological structure of a point pattern. This novel feature is free from isometric assumption. It can resist various deformations such as adding points, suppressing points, affine transformations, projective transformations and elastic transformations to some degree. A refinement solution of the well known scale invariant feature transform (SIFT) algorithm is also proposed based on the probabilistic analysis of this feature. Experimental results show that the proposed refinement solution for SIFT using this feature is effective and robust.

  8. Image Mosaic Method Based on SIFT Features of Line Segment

    Directory of Open Access Journals (Sweden)

    Jun Zhu

    2014-01-01

    Full Text Available This paper proposes a novel image mosaic method based on SIFT (Scale Invariant Feature Transform feature of line segment, aiming to resolve incident scaling, rotation, changes in lighting condition, and so on between two images in the panoramic image mosaic process. This method firstly uses Harris corner detection operator to detect key points. Secondly, it constructs directed line segments, describes them with SIFT feature, and matches those directed segments to acquire rough point matching. Finally, Ransac method is used to eliminate wrong pairs in order to accomplish image mosaic. The results from experiment based on four pairs of images show that our method has strong robustness for resolution, lighting, rotation, and scaling.

  9. Classifying algorithms for SIFT-MS technology and medical diagnosis.

    Science.gov (United States)

    Moorhead, K T; Lee, D; Chase, J G; Moot, A R; Ledingham, K M; Scotter, J; Allardyce, R A; Senthilmohan, S T; Endre, Z

    2008-03-01

    Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) is an analytical technique for real-time quantification of trace gases in air or breath samples. SIFT-MS system thus offers unique potential for early, rapid detection of disease states. Identification of volatile organic compound (VOC) masses that contribute strongly towards a successful classification clearly highlights potential new biomarkers. A method utilising kernel density estimates is thus presented for classifying unknown samples. It is validated in a simple known case and a clinical setting before-after dialysis. The simple case with nitrogen in Tedlar bags returned a 100% success rate, as expected. The clinical proof-of-concept with seven tests on one patient had an ROC curve area of 0.89. These results validate the method presented and illustrate the emerging clinical potential of this technology.

  10. n-SIFT: n-dimensional scale invariant feature transform.

    Science.gov (United States)

    Cheung, Warren; Hamarneh, Ghassan

    2009-09-01

    We propose the n-dimensional scale invariant feature transform (n-SIFT) method for extracting and matching salient features from scalar images of arbitrary dimensionality, and compare this method's performance to other related features. The proposed features extend the concepts used for 2-D scalar images in the computer vision SIFT technique for extracting and matching distinctive scale invariant features. We apply the features to images of arbitrary dimensionality through the use of hyperspherical coordinates for gradients and multidimensional histograms to create the feature vectors. We analyze the performance of a fully automated multimodal medical image matching technique based on these features, and successfully apply the technique to determine accurate feature point correspondence between pairs of 3-D MRI images and dynamic 3D + time CT data.

  11. A novel robot visual homing method based on SIFT features.

    Science.gov (United States)

    Zhu, Qidan; Liu, Chuanjia; Cai, Chengtao

    2015-10-14

    Warping is an effective visual homing method for robot local navigation. However, the performance of the warping method can be greatly influenced by the changes of the environment in a real scene, thus resulting in lower accuracy. In order to solve the above problem and to get higher homing precision, a novel robot visual homing algorithm is proposed by combining SIFT (scale-invariant feature transform) features with the warping method. The algorithm is novel in using SIFT features as landmarks instead of the pixels in the horizon region of the panoramic image. In addition, to further improve the matching accuracy of landmarks in the homing algorithm, a novel mismatching elimination algorithm, based on the distribution characteristics of landmarks in the catadioptric panoramic image, is proposed. Experiments on image databases and on a real scene confirm the effectiveness of the proposed method.

  12. Self-vibration cancellation of a novel bi-directional magnetized NdFeB/magnetostrictive/piezoelectric laminate

    Science.gov (United States)

    Leung, Chung Ming; Wang, Feifei; Wang, Ya

    2016-06-01

    A novel magnetoelectric (ME) laminated composite structure is proposed in this work, aiming to provide a good self-vibration cancellation performance under the magnetic field detection environment. The proposed structure consists of two Terfenol-D magnetostrictive alloy plates which are revised and length-magnetized by two NdFeB magnets bonded on the top surface of a thickness-polarized Pb(Zr, Ti)O3 (PZT) ceramic plate with separate electrodes. Experiments have shown that great vibration suppression up to 44 dB under harmonic disturbance was observed. The ME coefficient of the proposed structure also reaches up to ˜29 mV/Oe at non-resonance frequency and 758 mV/Oe at resonance frequency of 79 kHz which is ˜2 times larger than the traditional L-T Terfenol-D/PZT bilayer configuration of the same scale. Such performance improvement is achieved based on the bi-directional magnetic field bias (HBias) of two NdFeB magnets in magnetostrictive layer, internal in-series electrical wire connection in piezoelectric layer. The proposed design has great potential to be used for industrial applications associated with heavy environmental vibration noise.

  13. Angle-Resolved Scatter Measurements of Laser Damaged DKDP Crystals Using a Bi-Directional Scatter Diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Fluck, R; Wegner, P; Sheehan, L; Hackel, L A

    2000-12-22

    We built a bi-directional scatter diagnostics to measure and quantify losses due to scattering and absorption of harmonic conversion crystals (DKDP) for the National Ignition Facility (NIF). The main issues to be addressed are (1) amount of total energy reaching the target if the target hole was {+-}200 {micro}rad in size, (2) distribution of energy inside the target hole, (3) collateral damage of other optics by scattered light. The scatter diagnostics enables angle-resolved measurements at 351 nm, and is capable of both near specular transmission and large angle scatter measurements. In the near specular setup, the transmission can be measured within {+-}65 {micro}rad up to {+-}60 mrad acceptance angle. A silicon photo detector and a scientific-grade CCD camera provide total energy and energy distribution. A linear swing arm detection system enables large angle scatter measurements of 360{sup o}, in principal, with step sizes as small as 0.01{sup o} and different collection angle ranging between 1 and 20 mad. In this paper, scatter effects from laser damage and final finishing process of DKDP are discussed.

  14. Sifting Limits for the \\Lambda^2\\Lambda^- Sieve

    CERN Document Server

    Franze, Craig

    2010-01-01

    Sifting limits for the $\\Lambda^{2}\\Lambda^{-}$ sieve, Selberg's lower bound sieve, are computed for integral dimensions $1<\\kappa\\le10$. The evidence strongly suggests that for all $\\kappa\\ge3$ the $\\Lambda^{2}\\Lambda^{-}$ sieve is superior to the competing combinatorial sieves of Diamond, Halberstam, and Richert. A method initiated by Grupp and Richert for computing sieve functions for integral $\\kappa$ is also outlined.

  15. Gun bore flaw image matching based on improved SIFT descriptor

    Science.gov (United States)

    Zeng, Luan; Xiong, Wei; Zhai, You

    2013-01-01

    In order to increase the operation speed and matching ability of SIFT algorithm, the SIFT descriptor and matching strategy are improved. First, a method of constructing feature descriptor based on sector area is proposed. By computing the gradients histogram of location bins which are parted into 6 sector areas, a descriptor with 48 dimensions is constituted. It can reduce the dimension of feature vector and decrease the complexity of structuring descriptor. Second, it introduce a strategy that partitions the circular region into 6 identical sector areas starting from the dominate orientation. Consequently, the computational complexity is reduced due to cancellation of rotation operation for the area. The experimental results indicate that comparing with the OpenCV SIFT arithmetic, the average matching speed of the new method increase by about 55.86%. The matching veracity can be increased even under some variation of view point, illumination, rotation, scale and out of focus. The new method got satisfied results in gun bore flaw image matching. Keywords: Metrology, Flaw image matching, Gun bore, Feature descriptor

  16. Terrain Referenced Navigation Using SIFT Features in LiDAR Range-Based Data

    Science.gov (United States)

    2014-12-26

    TERRAIN REFERENCED NAVIGATION USING SIFT FEATURES IN LIDAR RANGE-BASED DATA THESIS Matthew T. Leines, Capt, USAF AFIT-ENG-MS-14-D-47 DEPARTMENT OF...subject to copyright protection in the United States. AFIT-ENG-MS-14-D-47 TERRAIN REFERENCED NAVIGATION USING SIFT FEATURES IN LIDAR RANGE-BASED DATA...UNLIMITED. AFIT-ENG-MS-14-D-47 TERRAIN REFERENCED NAVIGATION USING SIFT FEATURES IN LIDAR RANGE-BASED DATA Matthew T. Leines, BSECE, MSECE Capt, USAF

  17. 基于 SIFT 的图像匹配算法%Image Matching Algorithm Based on SIFT

    Institute of Scientific and Technical Information of China (English)

    周丽芬

    2014-01-01

    Key points are very few when extracted by the SIFT algorithm directly and mismatch points are much more during the image matching of the next step from blur image .We propose a matching algorithm based on SIFT feature .Firstly, we use the Laplacian operator to sharpen the blurred image in order to highlight the edge , and then extract the key points by the SIFT algo-rithm.Lastly, we use the bidirectional matching algorithm to match image .The experimental results show that the number of matched points by the improved algorithm has more points than the way of using SIFT algorithm directly and the results of matc -hing are better .%直接用SIFT算法对较模糊图像进行关键点提取时,提取的关键点个数较少且进行下一步匹配时错误匹配较多。提出一种基于SIFT特征的匹配算法,首先利用拉普拉斯算子对图像进行锐化处理,使其边缘得到突出,然后利用SIFT算法进行关键点提取,最后利用双向匹配算法进行图像匹配。实验结果表明,利用本文算法进行匹配比直接用SIFT算法进行匹配时的匹配点数更多,匹配效果更好。

  18. VISUAL TRACKING ALGORITHM BASED ON RANK SIFT%基于 SIFT 排序的视觉跟踪算法

    Institute of Scientific and Technical Information of China (English)

    孙超; 许悦雷; 查宇飞; 黄宏图

    2015-01-01

    Aiming at the impact of unstable key points on visual tracking algorithm which uses SIFT as its target feature,we present the rank SIFT-based visual tracking algorithm.To realise rank SIFT,we propose the spatial stability factor and the temporal stability factor and compose the importance weights with them for representing the significance of each key point.Based on rank SIFT,each key point takes part in tracking according to its own importance weight,so that the rank SIFT-based visual tracking is achieved.The algorithm overcomes the impact of unstable key points on tracking outcomes,therefore improves the accuracy and robustness of tracking.%针对不稳定的关键点对以 SIFT(Scale Invariant Feature Transform)为目标特征的视觉跟踪算法的影响,提出基于 SIFT 排序的视觉跟踪算法。为实现 SIFT 排序,提出空域稳定因子和时域稳定因子,并由此构成重要性权重,以表征各个特征点的重要程度。在 SIFT 排序的基础上,各个关键点按照重要性权重的不同参与跟踪,从而实现基于 SIFT 排序的视觉跟踪。该算法克服了不稳定的关键点对跟踪结果的影响,从而提高跟踪的准确性和鲁棒性。

  19. CHANGES IN CORTICAL KYNURENIC ACID BI-DIRECTIONALLY MODULATE PREFRONTAL GLUTAMATE LEVELS AS ASSESSED BY MICRODIALYSIS AND RAPID ELECTROCHEMISTRY

    Science.gov (United States)

    Konradsson-Geuken, Ȧ.; Gash, C. R.; Wu, H.-Q.; Alexander, K. S.; Pellicciari, R.; Schwarcz, R.; Bruno, J.P.

    2010-01-01

    Using two in vivo methods, microdialysis and rapid in situ electrochemistry, this study examined the modulation of extracellular glutamate levels by endogenously produced kynurenic acid (KYNA) in the prefrontal cortex (PFC) of awake rats. Measured by microdialysis, intraperitoneal (i.p.) administration of KYNA's bioprecursor L-kynurenine dose-dependently elevated extracellular KYNA and reduced extracellular glutamate (nadir after 50 mg/kg kynurenine: 60% decrease from baseline values). This dose-dependent decrease in glutamate levels was also seen using a glutamate-sensitive microelectrode array (MEA) (31% decrease following 50 mg/kg kynurenine). The kynurenine-induced reduction in glutamate was blocked (microdialysis) or attenuated (MEA) by co-administration of galantamine (3 mg/kg, i.p.), a drug that competes with KYNA at an allosteric potentiating site of the α7 nicotinic acetylcholine receptor. In separate experiments, extracellular glutamate levels were measured by MEA following the local perfusion (45 min) of the PFC with kynurenine (2.5 μM) or the selective KYNA biosynthesis inhibitor S-ethylsulfonylbenzoylalanine (S-ESBA; 5 mM). In agreement with previous microdialysis studies, systemic kynurenine application produced a reversible reduction in glutamate (nadir: −29%), whereas perfusion with S-ESBA increased glutamate levels reversibly (maximum: +38%). Collectively, these results demonstrate that fluctuations in the biosynthesis of KYNA in the PFC bi-directionally modulate extracellular glutamate levels, and that qualitatively very similar data are obtained by microdialysis and MEA. Since KYNA levels are elevated in the PFC of individuals with schizophrenia, and since prefrontal glutamatergic and nicotinic transmission mediate cognitive flexibility, normalization of KYNA levels in the PFC may constitute an effective treatment strategy for alleviating cognitive deficits in schizophrenia. PMID:20600676

  20. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Aqua-FM3_Edition1-CV)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2006-11-02] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  1. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Terra-FM2_Edition1)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2005-11-02] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  2. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Terra-FM1_Edition1-CV)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2006-11-02] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  3. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Aqua-FM4_Edition1)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2005-04-02] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  4. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Aqua-FM3_Edition2)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2006-01-01] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  5. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Terra-FM2_Edition1-CV)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2006-11-02] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  6. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Aqua-FM4_Edition1-CV)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2005-03-30] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  7. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Aqua-FM3_Edition1)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2005-11-02] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  8. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Terra-FM1_Edition2)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2006-01-01] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  9. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Terra-FM1_Edition1)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2005-11-02] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  10. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Terra-FM2_Edition2)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2006-01-01] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  11. CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Aqua-FM4_Edition2)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2005-03-29] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

  12. Development and analysis of the Software Implemented Fault-Tolerance (SIFT) computer

    Science.gov (United States)

    Goldberg, J.; Kautz, W. H.; Melliar-Smith, P. M.; Green, M. W.; Levitt, K. N.; Schwartz, R. L.; Weinstock, C. B.

    1984-01-01

    SIFT (Software Implemented Fault Tolerance) is an experimental, fault-tolerant computer system designed to meet the extreme reliability requirements for safety-critical functions in advanced aircraft. Errors are masked by performing a majority voting operation over the results of identical computations, and faulty processors are removed from service by reassigning computations to the nonfaulty processors. This scheme has been implemented in a special architecture using a set of standard Bendix BDX930 processors, augmented by a special asynchronous-broadcast communication interface that provides direct, processor to processor communication among all processors. Fault isolation is accomplished in hardware; all other fault-tolerance functions, together with scheduling and synchronization are implemented exclusively by executive system software. The system reliability is predicted by a Markov model. Mathematical consistency of the system software with respect to the reliability model has been partially verified, using recently developed tools for machine-aided proof of program correctness.

  13. Construction and analysis of a plant transformation binary vector pBDGG harboring a bi-directional promoter fusing dual visible reporter genes

    Institute of Scientific and Technical Information of China (English)

    Chunxiao Zhang; Ying Gai; Wenqi Wang; Yanyan Zhu; Xuemei Chen; Xiangning Jiang

    2008-01-01

    The constitutive promoter of cauliflower mosaic virus 35S (CaMV 35S) is a polar unidirectional promoter and is widely used in plantgenetic engineering.In the present study,the unidirectional CaMV 35S promoter has been modified to a bi-directional promoter by fusing its minimal promoter element to the 5' end of CaMV 35S promoter in the opposite orientation.To qualitatively and quantitatively esti-mate its bi-directional Wanscriptionai function and activity,two visible reporter genes,gusA β-glucuronidase,GUS) and gfp (green fluo-rescent protein,GFP),were fused to the two ends of the promoter in bi-orientations ending with NOS terminator sequences,respectively.Stable expression of gusA and gfp genes in transgenic tobacco (Nicotiana tabacum L.) was visulized by histochemically staining for GUS and fluorescence microscopic observation under UV for GFP in transgenic plants.The expression of two reporter genes showed that the eonsuructed bi-directional promoter did have the bi-directional transcriptional function in both expected orientations.The quantitativeestimation of GUS and GFP were determined on a HITACHI F1000 Fluorescence Spectrophotometer with various wavelengths of excita-tion and emission.The GUS activity varied from 8 to 250 pmol 4-MU/min/mg protein and the GFP content varied from 0.9 to 1.8 μg/mg protein in various lines of transgenic tobacco plants.Higher GUS activity generally coupled with lower GFP content,and vice versa.

  14. Image feature extraction in encrypted domain with privacy-preserving SIFT.

    Science.gov (United States)

    Hsu, Chao-Yung; Lu, Chun-Shien; Pei, Soo-Chang

    2012-11-01

    Privacy has received considerable attention but is still largely ignored in the multimedia community. Consider a cloud computing scenario where the server is resource-abundant, and is capable of finishing the designated tasks. It is envisioned that secure media applications with privacy preservation will be treated seriously. In view of the fact that scale-invariant feature transform (SIFT) has been widely adopted in various fields, this paper is the first to target the importance of privacy-preserving SIFT (PPSIFT) and to address the problem of secure SIFT feature extraction and representation in the encrypted domain. As all of the operations in SIFT must be moved to the encrypted domain, we propose a privacy-preserving realization of the SIFT method based on homomorphic encryption. We show through the security analysis based on the discrete logarithm problem and RSA that PPSIFT is secure against ciphertext only attack and known plaintext attack. Experimental results obtained from different case studies demonstrate that the proposed homomorphic encryption-based privacy-preserving SIFT performs comparably to the original SIFT and that our method is useful in SIFT-based privacy-preserving applications.

  15. Design study of Software-Implemented Fault-Tolerance (SIFT) computer

    Science.gov (United States)

    Wensley, J. H.; Goldberg, J.; Green, M. W.; Kutz, W. H.; Levitt, K. N.; Mills, M. E.; Shostak, R. E.; Whiting-Okeefe, P. M.; Zeidler, H. M.

    1982-01-01

    Software-implemented fault tolerant (SIFT) computer design for commercial aviation is reported. A SIFT design concept is addressed. Alternate strategies for physical implementation are considered. Hardware and software design correctness is addressed. System modeling and effectiveness evaluation are considered from a fault-tolerant point of view.

  16. Face Recognition via Ensemble SIFT Matching of Uncorrelated Hyperspectral Bands and Spectral PCTs

    Science.gov (United States)

    2011-06-01

    Unsupervised Hyperspectral Target Detection Algorithm. Wright-Patterson AFB: Air Force Institute of Technology. Kirby, M., & Sirovich, L. (1990...Xu, Y., Hu, K., Tian, Y., & Peng, F. (2008). Classification of Hyperspectral imagery using SIFT for spectral matching. Image and Signal Processing...single hyperspectral band which also performs very well under temporal variation. 15. SUBJECT TERMS Face Recognition, SIFT, Ensemble Classification

  17. The Hierarchical Specification and Mechanical Verification of the SIFT Design

    Science.gov (United States)

    1983-01-01

    The formal specification and proof methodology employed to demonstrate that the SIFT computer system meets its requirements are described. The hierarchy of design specifications is shown, from very abstract descriptions of system function down to the implementation. The most abstract design specifications are simple and easy to understand, almost all details of the realization were abstracted out, and are used to ensure that the system functions reliably and as intended. A succession of lower level specifications refines these specifications into more detailed, and more complex, views of the system design, culminating in the Pascal implementation. The section describes the rigorous mechanical proof that the abstract specifications are satisfied by the actual implementation.

  18. Weighted Multi-Scale Image Matching Based on Harris-Sift Descriptor

    Directory of Open Access Journals (Sweden)

    Can Sun

    2013-10-01

    Full Text Available According to the rotational invariance of Harris corner detectorand the robustness of Sift descriptor. An improved Harris-Sift corner descriptor was proposed. At first, the algorithm given multi-scale strategy to Harris corner, improved corner counting method and removed redundant points at the same time, then, the corner was directly applied to low-pass Gaussian filter image. Based on the histogram of Sift feature descriptor, generates a new 128-dimensional feature vector descriptor by multi-scale Gauss weighted.Through the above, Harris corner detectorand Sift descriptorwas normalizedin the scale layer and gradient features. The experiment results indicated that, the improved corner descriptorcomprised both advantage of Harris corner detection and Sift feature descriptor. The method reduced the computation time and the false match rate, which could be validly applied to the robotstereo vision matching andthree-dimensional reconstruction.      

  19. Live-cell tracking using SIFT features in DIC microscopic videos.

    Science.gov (United States)

    Jiang, Richard M; Crookes, Danny; Luo, Nie; Davidson, Michael W

    2010-09-01

    In this paper, a novel motion-tracking scheme using scale-invariant features is proposed for automatic cell motility analysis in gray-scale microscopic videos, particularly for the live-cell tracking in low-contrast differential interference contrast (DIC) microscopy. In the proposed approach, scale-invariant feature transform (SIFT) points around live cells in the microscopic image are detected, and a structure locality preservation (SLP) scheme using Laplacian Eigenmap is proposed to track the SIFT feature points along successive frames of low-contrast DIC videos. Experiments on low-contrast DIC microscopic videos of various live-cell lines shows that in comparison with principal component analysis (PCA) based SIFT tracking, the proposed Laplacian-SIFT can significantly reduce the error rate of SIFT feature tracking. With this enhancement, further experimental results demonstrate that the proposed scheme is a robust and accurate approach to tackling the challenge of live-cell tracking in DIC microscopy.

  20. Automated Photogrammetric Image Matching with Sift Algorithm and Delaunay Triangulation

    Science.gov (United States)

    Karagiannis, Georgios; Antón Castro, Francesc; Mioc, Darka

    2016-06-01

    An algorithm for image matching of multi-sensor and multi-temporal satellite images is developed. The method is based on the SIFT feature detector proposed by Lowe in (Lowe, 1999). First, SIFT feature points are detected independently in two images (reference and sensed image). The features detected are invariant to image rotations, translations, scaling and also to changes in illumination, brightness and 3-dimensional viewpoint. Afterwards, each feature of the reference image is matched with one in the sensed image if, and only if, the distance between them multiplied by a threshold is shorter than the distances between the point and all the other points in the sensed image. Then, the matched features are used to compute the parameters of the homography that transforms the coordinate system of the sensed image to the coordinate system of the reference image. The Delaunay triangulations of each feature set for each image are computed. The isomorphism of the Delaunay triangulations is determined to guarantee the quality of the image matching. The algorithm is implemented in Matlab and tested on World-View 2, SPOT6 and TerraSAR-X image patches.

  1. PhyloSift: phylogenetic analysis of genomes and metagenomes

    Directory of Open Access Journals (Sweden)

    Aaron E. Darling

    2014-01-01

    Full Text Available Like all organisms on the planet, environmental microbes are subject to the forces of molecular evolution. Metagenomic sequencing provides a means to access the DNA sequence of uncultured microbes. By combining DNA sequencing of microbial communities with evolutionary modeling and phylogenetic analysis we might obtain new insights into microbiology and also provide a basis for practical tools such as forensic pathogen detection.In this work we present an approach to leverage phylogenetic analysis of metagenomic sequence data to conduct several types of analysis. First, we present a method to conduct phylogeny-driven Bayesian hypothesis tests for the presence of an organism in a sample. Second, we present a means to compare community structure across a collection of many samples and develop direct associations between the abundance of certain organisms and sample metadata. Third, we apply new tools to analyze the phylogenetic diversity of microbial communities and again demonstrate how this can be associated to sample metadata.These analyses are implemented in an open source software pipeline called PhyloSift. As a pipeline, PhyloSift incorporates several other programs including LAST, HMMER, and pplacer to automate phylogenetic analysis of protein coding and RNA sequences in metagenomic datasets generated by modern sequencing platforms (e.g., Illumina, 454.

  2. Performance Analysis of the SIFT Operator for Automatic Feature Extraction and Matching in Photogrammetric Applications.

    Science.gov (United States)

    Lingua, Andrea; Marenchino, Davide; Nex, Francesco

    2009-01-01

    In the photogrammetry field, interest in region detectors, which are widely used in Computer Vision, is quickly increasing due to the availability of new techniques. Images acquired by Mobile Mapping Technology, Oblique Photogrammetric Cameras or Unmanned Aerial Vehicles do not observe normal acquisition conditions. Feature extraction and matching techniques, which are traditionally used in photogrammetry, are usually inefficient for these applications as they are unable to provide reliable results under extreme geometrical conditions (convergent taking geometry, strong affine transformations, etc.) and for bad-textured images. A performance analysis of the SIFT technique in aerial and close-range photogrammetric applications is presented in this paper. The goal is to establish the suitability of the SIFT technique for automatic tie point extraction and approximate DSM (Digital Surface Model) generation. First, the performances of the SIFT operator have been compared with those provided by feature extraction and matching techniques used in photogrammetry. All these techniques have been implemented by the authors and validated on aerial and terrestrial images. Moreover, an auto-adaptive version of the SIFT operator has been developed, in order to improve the performances of the SIFT detector in relation to the texture of the images. The Auto-Adaptive SIFT operator (A(2) SIFT) has been validated on several aerial images, with particular attention to large scale aerial images acquired using mini-UAV systems.

  3. Midsagittal plane extraction from brain images based on 3D SIFT.

    Science.gov (United States)

    Wu, Huisi; Wang, Defeng; Shi, Lin; Wen, Zhenkun; Ming, Zhong

    2014-03-21

    Midsagittal plane (MSP) extraction from 3D brain images is considered as a promising technique for human brain symmetry analysis. In this paper, we present a fast and robust MSP extraction method based on 3D scale-invariant feature transform (SIFT). Unlike the existing brain MSP extraction methods, which mainly rely on the gray similarity, 3D edge registration or parameterized surface matching to determine the fissure plane, our proposed method is based on distinctive 3D SIFT features, in which the fissure plane is determined by parallel 3D SIFT matching and iterative least-median of squares plane regression. By considering the relative scales, orientations and flipped descriptors between two 3D SIFT features, we propose a novel metric to measure the symmetry magnitude for 3D SIFT features. By clustering and indexing the extracted SIFT features using a k-dimensional tree (KD-tree) implemented on graphics processing units, we can match multiple pairs of 3D SIFT features in parallel and solve the optimal MSP on-the-fly. The proposed method is evaluated by synthetic and in vivo datasets, of normal and pathological cases, and validated by comparisons with the state-of-the-art methods. Experimental results demonstrated that our method has achieved a real-time performance with better accuracy yielding an average yaw angle error below 0.91° and an average roll angle error no more than 0.89°.

  4. Performance Analysis of the SIFT Operator for Automatic Feature Extraction and Matching in Photogrammetric Applications

    Directory of Open Access Journals (Sweden)

    Francesco Nex

    2009-05-01

    Full Text Available In the photogrammetry field, interest in region detectors, which are widely used in Computer Vision, is quickly increasing due to the availability of new techniques. Images acquired by Mobile Mapping Technology, Oblique Photogrammetric Cameras or Unmanned Aerial Vehicles do not observe normal acquisition conditions. Feature extraction and matching techniques, which are traditionally used in photogrammetry, are usually inefficient for these applications as they are unable to provide reliable results under extreme geometrical conditions (convergent taking geometry, strong affine transformations, etc. and for bad-textured images. A performance analysis of the SIFT technique in aerial and close-range photogrammetric applications is presented in this paper. The goal is to establish the suitability of the SIFT technique for automatic tie point extraction and approximate DSM (Digital Surface Model generation. First, the performances of the SIFT operator have been compared with those provided by feature extraction and matching techniques used in photogrammetry. All these techniques have been implemented by the authors and validated on aerial and terrestrial images. Moreover, an auto-adaptive version of the SIFT operator has been developed, in order to improve the performances of the SIFT detector in relation to the texture of the images. The Auto-Adaptive SIFT operator (A2 SIFT has been validated on several aerial images, with particular attention to large scale aerial images acquired using mini-UAV systems.

  5. Ambient analysis of trace compounds in gaseous media by SIFT-MS.

    Science.gov (United States)

    Smith, David; Spaněl, Patrik

    2011-05-21

    The topic of ambient gas analysis has been rapidly developed in the last few years with the evolution of the exciting new techniques such as DESI, DART and EESI. The essential feature of all is that analysis of trace gases can be accomplished either in the gas phase or those released from surfaces, crucially avoiding sample collection or modification. In this regard, selected ion flow tube mass spectrometry, SIFT-MS, also performs ambient analyses both accurately and rapidly. In this focused review we describe the underlying ion chemistry underpinning SIFT-MS through a discourse on the reactions of different classes of organic and inorganic molecules with H(3)O(+), NO(+) and O(2)(+)˙ studied using the SIFT technique. Rate coefficients and ion products of these reactions facilitate absolute SIFT-MS analyses and can also be useful for the interpretation of data obtained by the other ambient analysis methods mentioned above. The essential physics and flow dynamics of SIFT-MS are described that, together with the reaction kinetics, allow SIFT-MS to perform absolute ambient analyses of trace compounds in humid atmospheric air, exhaled breath and the headspace of aqueous liquids. Several areas of research that, through pilot experiments, are seen to benefit from ambient gas analysis using SIFT-MS are briefly reviewed. Special attention is given to exhaled breath and urine headspace analysis directed towards clinical diagnosis and therapeutic monitoring, and some other areas researched using SIFT-MS are summarised. Finally, extensions to current areas of application and indications of other directions in which SIFT-MS can be exploited for ambient analysis are alluded to.

  6. A novel PWM control for a bi-directional full-bridge DC-DC converter with smooth conversion mode transitions

    Science.gov (United States)

    Lorentz, V. R. H.; Schwarzmann, H.; März, M.; Bauer, A. J.; Ryssel, H.; Frey, L.; Poure, P.; Braun, F.

    2011-08-01

    A novel CMOS integrated pulse-width modulation (PWM) control circuit allowing smooth transitions between conversion modes in full-bridge based bi-directional DC-DC converters operating at high switching frequencies is presented. The novel PWM control circuit is able to drive full-bridge based DC-DC converters performing step-down (i.e. buck) and step-up (i.e. boost) voltage conversion in both directions, thus allowing charging and discharging of the batteries in mobile systems. It provides smooth transitions between buck, buck-boost and boost modes. Additionally, the novel PWM control loop circuit uses a symmetrical triangular carrier, which overcomes the necessity of using an output phasing circuit previously required in PWM controllers based on sawtooth oscillators. The novel PWM control also enables to build bi-directional DC-DC converters operating at high switching frequencies (i.e. up to 10 MHz and above). Finally, the proposed PWM control circuit also allows the use of an average lossless inductor-current sensor for sensing the average load current even at very high switching frequencies. In this article, the proposed PWM control circuit is modelled and the integrated CMOS schematic is given. The corresponding theory is analysed and presented in detail. The circuit simulations realised in the Cadence Spectre software with a commercially available 0.18 µm mixed-signal CMOS technology from UMC are shown. The PWM control circuit was implemented in a monolithic integrated bi-directional CMOS DC-DC converter ASIC prototype. The fabricated prototype was tested experimentally and has shown performances in accordance with the theory.

  7. The enhancement effect of pp38 gene product on the activity of its upstream bi-directional promoter in Marek's disease virus

    Institute of Scientific and Technical Information of China (English)

    DING; Jiabo; CUI; Zhizhong; JIANG; Shijin; REDDY; Sanjay

    2006-01-01

    There was a bi-directional promoter between gene 38 kd phosphorylated protein (pp38) gene and 1.8-kb mRNA transcript gene family in the genome of Marek's disease virus (MDV). In this study, enhanced green fluorescence protein (EGFP) reporter plamids, pP(pp38)-EGFP and pP(1.8- kb)-EGFP, were constructed under this bi-directional promoter in two directions. The two plasmids were transfected into uninfected chicken embryo fibroblast (CEF), MDV clone rMd5 infected CEF (rMd5-CEF) and pp38-deleted derivative rMd5Δpp38 infected CEF (rMd5Δpp38-CEF) respectively. Transfection analysis showed that EGFP was only expressed in rMd5-CEF, and no EGFP could be detected in uninfected CEF or rMd5Δpp38-CEF, implying that pp38 was a factor influencing the activity of the promoter. The pp38-expressing recombinant plasmid pcDNA-pp38 was constructed to co- transfect CEF or rMd5Δpp38-CEF with pP(pp38)-EGFP or pP(1.8-kb)-EGFP. In this case, EGFP could be detected only in rMd5Δpp38-CEF but still not in uninfected CEF, implying that pp38 needs other protein(s) to work together for the complete trans-acting activity. Another MDV gene, 24 kd phosphorylated protein pp24 gene was cloned into pcDNA3.1 as a pp24-expressing recombinant plasmid pcDNA-pp24. When uninfected CEF was co-transfected with pcDNA-pp38, pcDNA-pp24 and EGFP expressing plasmids pP(pp38)-EGFP or pP(1.8-kb)-EGFP, the EGFP could be detected. These results indicated that pp38 and pp24 could enhance the activity of the promoter when they worked together. DNA mobility shift assay showed that pp38 would bind to the bi-directional promoter with the co-existing of pp24, although neither of them alone influenced mobility of the promoter DNA. All the above suggested that MDV pp38 could transactivate the bi-directional promoter when combined with pp24. The results also indicated that the activity of the promoter in the direction of 1.8-kb mRNA was significantly stronger than that of pp38 direction.

  8. Simulation analysis of one-stage C+L-band erbium-doped fiber ASE source with double-pass bi-directional pumping configuration

    Institute of Scientific and Technical Information of China (English)

    Wencai Huang(黄文财); Hai Ming(明海)

    2004-01-01

    A new technique to generate a C+L-band flat amplified spontaneous emission (ASE) source in one-stage erbium-doped fiber (EDF) using bi-directional pumping configuration is analyzed. The simulation results show that the key point of obtaining flat C+L-band ASE spectrum in one-stage EDF is using a laser diode operated at 980 nm as backward pump source. ASE source with nearly 80-nm bandwidth can be obtained by means of selecting suitable fiber length and properly adjusting the ratio of forward to backward pump power.

  9. Analysis and Design of Bi-Directional DC-DC Converter in the Extended Run Time DC UPS System Based on Fuel Cell and Supercapacitor

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2009-01-01

    input voltage combined with load current feedback using PI controller with anti-windup scheme to realize closed-loop control of the whole system, and verify the feasibility of the control scheme proposed by simulation. A 1kW prototype controlled by TMS320F2808 DSP is implemented and tested. Experimental......Abstract-In this paper, an extended run time DC UPS system structure with fuel cell and supercapacitor is investigated. A wide input range bi-directional dc-dc converter is described along with the phase-shift modulation scheme and phase-shift with duty cycle control, in different modes...

  10. An assessment of the real-time application capabilities of the SIFT computer system

    Science.gov (United States)

    Butler, R. W.

    1982-01-01

    The real-time capabilities of the SIFT computer system, a highly reliable multicomputer architecture developed to support the flight controls of a relaxed static stability aircraft, are discussed. The SIFT computer system was designed to meet extremely high reliability requirements and to facilitate a formal proof of its correctness. Although SIFT represents a significant achievement in fault-tolerant system research it presents an unusual and restrictive interface to its users. The characteristics of the user interface and its impact on application system design are assessed.

  11. Reconstruction of volumetric ultrasound panorama based on improved 3D SIFT.

    Science.gov (United States)

    Ni, Dong; Chui, Yim Pan; Qu, Yingge; Yang, Xuan; Qin, Jing; Wong, Tien-Tsin; Ho, Simon S H; Heng, Pheng Ann

    2009-10-01

    Registration of ultrasound volumes is a key issue for the reconstruction of volumetric ultrasound panorama. In this paper, we propose an improved three-dimensional (3D) scale invariant feature transform (SIFT) algorithm to globally register ultrasound volumes acquired from dedicated ultrasound probe, where local deformations are corrected by block-based warping algorithm. Original SIFT algorithm is extended to 3D and improved by combining the SIFT detector with Rohr3D detector to extract complementary features and applying the diffusion distance algorithm for robust feature comparison. Extensive experiments have been performed on both phantom and clinical data sets to demonstrate the effectiveness and robustness of our approach.

  12. Combinatorial Constructions for Sifting Primes and Enumerating the Rationals

    CERN Document Server

    Gnang, Edinah K

    2012-01-01

    We describe a combinatorial approach for investigating properties of rational numbers. The overall approach rests on structural bijections between rational numbers and familiar combinatorial objects, namely rooted trees. We emphasize that such mappings achieve much more than enumeration of rooted trees. We discuss two related structural bijections. The first corresponds to a bijective map between integers and rooted trees. The first bijection also suggests a new algorithm for sifting primes. The second bijection extends the first one in order to map rational numbers to a family of rooted trees. The second bijection suggests a new combinatorial construction for generating reduced rational numbers, thereby producing refinements of the output of the Wilf-Calkin[1] Algorithm.

  13. Face Identification from Manipulated Facial Images using SIFT

    CERN Document Server

    Chennamma, H R; Veerabhadrappa,

    2011-01-01

    Editing on digital images is ubiquitous. Identification of deliberately modified facial images is a new challenge for face identification system. In this paper, we address the problem of identification of a face or person from heavily altered facial images. In this face identification problem, the input to the system is a manipulated or transformed face image and the system reports back the determined identity from a database of known individuals. Such a system can be useful in mugshot identification in which mugshot database contains two views (frontal and profile) of each criminal. We considered only frontal view from the available database for face identification and the query image is a manipulated face generated by face transformation software tool available online. We propose SIFT features for efficient face identification in this scenario. Further comparative analysis has been given with well known eigenface approach. Experiments have been conducted with real case images to evaluate the performance of ...

  14. Volumetric ultrasound panorama based on 3D SIFT.

    Science.gov (United States)

    Ni, Dong; Qul, Yingge; Yang, Xuan; Chui, Yim Pan; Wong, Tien-Tsin; Ho, Simon S M; Heng, Pheng Ann

    2008-01-01

    The reconstruction of three-dimensional (3D) ultrasound panorama from multiple ultrasound volumes can provide a wide field of view for better clinical diagnosis. Registration of ultrasound volumes has been a key issue for the success of this panoramic process. In this paper, we propose a method to register and stitch ultrasound volumes, which are scanned by dedicated ultrasound probe, based on an improved 3D Scale Invariant Feature Transform (SIFT) algorithm. We propose methods to exclude artifacts from ultrasound images in order to improve the overall performance in 3D feature point extraction and matching. Our method has been validated on both phantom and clinical data sets of human liver. Experimental results show the effectiveness and stability of our approach, and the precision of our method is comparable to that of the position tracker based registration.

  15. Robust and Efficient Sifting-Less Quantum Key Distribution Protocols

    CERN Document Server

    Grosshans, Frédéric

    2009-01-01

    We show that replacing the usual sifting step of the standard quantum-key-distribution protocol BB84 by a one-way reverse reconciliation procedure increases its robustness against photon-number-splitting (PNS) attacks to the level of the SARG04 protocol while keeping the raw key-rate of BB84. This protocol, which uses the same state and detection than BB84, is the m=4 member of a protocol-family using m polarization states which we introduce here. We show that the robustness of these protocols against PNS attacks increases exponentially with m, and that the effective keyrate of optimized weak coherent pulses decreases with the transmission T like T^{1+1/(m-2)}.

  16. SIFT: Spherical-deconvolution informed filtering of tractograms.

    Science.gov (United States)

    Smith, Robert E; Tournier, Jacques-Donald; Calamante, Fernando; Connelly, Alan

    2013-02-15

    Diffusion MRI allows the structural connectivity of the whole brain (the 'tractogram') to be estimated in vivo non-invasively using streamline tractography. The biological accuracy of these data sets is however limited by the inherent biases associated with the reconstruction method. Here we propose a method to retrospectively improve the accuracy of these reconstructions, by selectively filtering out streamlines from the tractogram in a manner that improves the fit between the streamline reconstruction and the underlying diffusion images. This filtering is guided by the results of spherical deconvolution of the diffusion signal, hence the acronym SIFT: spherical-deconvolution informed filtering of tractograms. Data sets processed by this algorithm show a marked reduction in known reconstruction biases, and improved biological plausibility. Emerging methods in diffusion MRI, particularly those that aim to characterise and compare the structural connectivity of the brain, should benefit from the improved accuracy of the reconstruction.

  17. Face recognition using SIFT features under 3D meshes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cheng; GU Yu-zhang; HU Ke-li; WANG Ying-guan

    2015-01-01

    Expression, occlusion, and pose variations are three main challenges for 3D face recognition. A novel method is presented to address 3D face recognition using scale-invariant feature transform (SIFT) features on 3D meshes. After preprocessing, shape index extrema on the 3D facial surface are selected as keypoints in the difference scale space and the unstable keypoints are removed after two screening steps. Then, a local coordinate system for each keypoint is established by principal component analysis (PCA). Next, two local geometric features are extracted around each keypoint through the local coordinate system. Additionally, the features are augmented by the symmetrization according to the approximate left-right symmetry in human face. The proposed method is evaluated on the Bosphorus, BU-3DFE, and Gavab databases, respectively. Good results are achieved on these three datasets. As a result, the proposed method proves robust to facial expression variations, partial external occlusions and large pose changes.

  18. MR imaging of the brain in large cohort studies: feasibility report of the population- and patient-based BiDirect study

    Energy Technology Data Exchange (ETDEWEB)

    Teuber, Anja; Berger, Klaus; Wersching, Heike [University of Muenster, Institute of Epidemiology and Social Medicine, Muenster (Germany); Sundermann, Benedikt; Kugel, Harald; Schwindt, Wolfram; Heindel, Walter [University Hospital Muenster, Department of Clinical Radiology, Muenster (Germany); Minnerup, Jens [University Hospital Muenster, Department of Neurology, Muenster (Germany); Dannlowski, Udo [University of Muenster, Department of Psychiatry, Muenster (Germany); University of Marburg, Department of Psychiatry, Marburg (Germany)

    2017-01-15

    To describe the implementation and protocol of cerebral magnetic resonance imaging (MRI) in the longitudinal BiDirect study and to report rates of study participation as well as management of incidental findings. Data came from the BiDirect study that investigates the relationship between depression and arteriosclerosis and comprises 2258 participants in three cohorts: 999 patients with depression, 347 patients with manifest cardiovascular disease (CVD) and 912 population-based controls. The study program includes MRI of the brain. Reasons for non-participation were systematically collected. Incidental findings were categorized and disclosed according to clinical relevance. At baseline 2176 participants were offered MRI, of whom 1453 (67 %) completed it. Reasons for non-participation differed according to cohort, age and gender with controls showing the highest participation rate of 79 %. Patient cohorts had higher refusal rates and CVD patients a high prevalence of contraindications. In the first follow-up examination 69 % of participating subjects completed MRI. Incidental findings were disclosed to 246 participants (17 %). The majority of incidental findings were extensive white matter hyperintensities requiring further diagnostic work-up. Knowledge about subjects and sensible definition of incidental findings are crucial for large-scale imaging projects. Our data offer practical and concrete information for the design of future studies. (orig.)

  19. Relaxed damage threshold intensity conditions and nonlinear increase in the conversion efficiency of an optical parametric oscillator using a bi-directional pump geometry.

    Science.gov (United States)

    Norris, G; McConnell, G

    2010-03-01

    A novel bi-directional pump geometry that nonlinearly increases the nonlinear optical conversion efficiency of a synchronously pumped optical parametric oscillator (OPO) is reported. This bi-directional pumping method synchronizes the circulating signal pulse with two counter-propagating pump pulses within a linear OPO resonator. Through this pump scheme, an increase in nonlinear optical conversion efficiency of 22% was achieved at the signal wavelength, corresponding to a 95% overall increase in average power. Given an almost unchanged measured pulse duration of 260 fs under optimal performance conditions, this related to a signal wavelength peak power output of 18.8 kW, compared with 10 kW using the traditional single-pass geometry. In this study, a total effective peak intensity pump-field of 7.11 GW/cm(2) (corresponding to 3.55 GW/cm(2) from each pump beam) was applied to a 3 mm long periodically poled lithium niobate crystal, which had a damage threshold intensity of 4 GW/cm(2), without impairing crystal integrity. We therefore prove the application of this novel pump geometry provides opportunities for power-scaling of synchronously pumped OPO systems together with enhanced nonlinear conversion efficiency through relaxed damage threshold intensity conditions.

  20. Cross-indexing of binary SIFT codes for large-scale image search.

    Science.gov (United States)

    Liu, Zhen; Li, Houqiang; Zhang, Liyan; Zhou, Wengang; Tian, Qi

    2014-05-01

    In recent years, there has been growing interest in mapping visual features into compact binary codes for applications on large-scale image collections. Encoding high-dimensional data as compact binary codes reduces the memory cost for storage. Besides, it benefits the computational efficiency since the computation of similarity can be efficiently measured by Hamming distance. In this paper, we propose a novel flexible scale invariant feature transform (SIFT) binarization (FSB) algorithm for large-scale image search. The FSB algorithm explores the magnitude patterns of SIFT descriptor. It is unsupervised and the generated binary codes are demonstrated to be dispreserving. Besides, we propose a new searching strategy to find target features based on the cross-indexing in the binary SIFT space and original SIFT space. We evaluate our approach on two publicly released data sets. The experiments on large-scale partial duplicate image retrieval system demonstrate the effectiveness and efficiency of the proposed algorithm.

  1. Efficient bit sifting scheme of post-processing in quantum key distribution

    Science.gov (United States)

    Li, Qiong; Le, Dan; Wu, Xianyan; Niu, Xiamu; Guo, Hong

    2015-10-01

    Bit sifting is an important step in the post-processing of quantum key distribution (QKD). Its function is to sift out the undetected original keys. The communication traffic of bit sifting has essential impact on the net secure key rate of a practical QKD system. In this paper, an efficient bit sifting scheme is presented, of which the core is a lossless source coding algorithm. Both theoretical analysis and experimental results demonstrate that the performance of the scheme is approaching the Shannon limit. The proposed scheme can greatly decrease the communication traffic of the post-processing of a QKD system, which means the proposed scheme can decrease the secure key consumption for classical channel authentication and increase the net secure key rate of the QKD system, as demonstrated by analyzing the improvement on the net secure key rate. Meanwhile, some recommendations on the application of the proposed scheme to some representative practical QKD systems are also provided.

  2. The SIFT hardware/software systems. Volume 1: A detailed description

    Science.gov (United States)

    Palumbo, Daniel L.

    1985-01-01

    This report contains a detailed description of the software implemented fault-tolerant computer's operating system and hardware subsystems. The Software Implemented Fault-Tolerant (SIFT) computer system was developed as an experimental vehicle for fault-tolerant systems research. The SIFT effort began with broad, in-depth studies stating the reliability and processing requirements for digital computers which would, in the aircraft of the 1990's, control flight-critical functions.

  3. PCA-SIFT 特征匹配算法研究%Research on the matching algorithm of PCA-SIFT

    Institute of Scientific and Technical Information of China (English)

    李钦; 游雄; 李科; 张彦喜

    2016-01-01

    SIFT特征具有旋转、尺度和明暗变化的不变性,在图像匹配中得到广泛应用。针对SIFT 特征匹配中耗时长、匹配点对少、准确率低的问题,提出PCA‐SIFT特征匹配的方法。使用更加精简的方法构建特征点描述向量,通过预先构建的投影矩阵对描述向量进行主成分分析,降低描述向量的维度从而提高了特征匹配的速度,同时降维也对描述向量进行了去噪提纯,使得匹配更加准确。实验证明,利用PCA‐SIFT 特征进行匹配在降低匹配耗时的同时,增加了匹配点对,匹配准确率也得到提高。%SIFT is widely used in the feature matching because it is resistant to the rotation ,scale and illumination changes .The matching method of PCA‐SIFT is proposed aiming at the problems of time‐consuming ,fewer matching points and low accuracy rate in SIFT .A simplified method is adopted to build the descriptor .T he process of PCA reduces the dimensionality of the key point descriptors and improves the matching efficiency .In addition ,reducing the dimension is also helpful to denoise the description vector ,which makes feature matching more accurate .The experiments prove that the PCA‐SIFT proposed in the paper can reduce the matching time ,increase the number of matching points and improve the accuracy rate .

  4. Edge-SIFT: discriminative binary descriptor for scalable partial-duplicate mobile search.

    Science.gov (United States)

    Zhang, Shiliang; Tian, Qi; Lu, Ke; Huang, Qingming; Gao, Wen

    2013-07-01

    As the basis of large-scale partial duplicate visual search on mobile devices, image local descriptor is expected to be discriminative, efficient, and compact. Our study shows that the popularly used histogram-based descriptors, such as scale invariant feature transform (SIFT) are not optimal for this task. This is mainly because histogram representation is relatively expensive to compute on mobile platforms and loses significant spatial clues, which are important for improving discriminative power and matching near-duplicate image patches. To address these issues, we propose to extract a novel binary local descriptor named Edge-SIFT from the binary edge maps of scale- and orientation-normalized image patches. By preserving both locations and orientations of edges and compressing the sparse binary edge maps with a boosting strategy, the final Edge-SIFT shows strong discriminative power with compact representation. Furthermore, we propose a fast similarity measurement and an indexing framework with flexible online verification. Hence, the Edge-SIFT allows an accurate and efficient image search and is ideal for computation sensitive scenarios such as a mobile image search. Experiments on a large-scale dataset manifest that the Edge-SIFT shows superior retrieval accuracy to Oriented BRIEF (ORB) and is superior to SIFT in the aspects of retrieval precision, efficiency, compactness, and transmission cost.

  5. Performance Assessment of Bi-Directional Knotless Tissue-Closure Devices in Juvenile Chinook Salmon Surgically Implanted with Acoustic Transmitters, 2009 - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Woodley, Christa M.; Wagner, Katie A.; Bryson, Amanda J.

    2012-11-09

    The purpose of this report is to assess the performance of bi-directional knotless tissue-closure devices for use in tagging juvenile salmon. This study is part of an ongoing effort at Pacific Northwest National Laboratory (PNNL) to reduce unwanted effects of tags and tagging procedures on the survival and behavior of juvenile salmonids, by assessing and refining suturing techniques, suture materials, and tag burdens. The objective of this study was to compare the performance of the knotless (barbed) suture, using three different suture patterns (treatments: 6-point, Wide “N”, Wide “N” Knot), to the current method of suturing (MonocrylTM monofilament, discontinuous sutures with a 2×2×2×2 knot) used in monitoring and research programs with a novel antiseptic barrier on the wound (“Second Skin”).

  6. A validation of a ray-tracing tool used to generate bi-directional scattering distribution functions for complex fenestration systems

    DEFF Research Database (Denmark)

    McNeil, A.; Jonsson, C.J.; Appelfeld, David

    2013-01-01

    Fenestration attachments are anticipated to produce significant reductions in building energy use because they can be deployed quickly at low-cost. New software tools enable users to assess the building energy impacts of optically complex fenestration systems (CFS) such as shades, Venetian blinds......, or daylighting systems. However, such tools require users to provide bi-directional scattering distribution function (BSDF) data that describe the solar-optical performance of the CFS. A free, open-source Radiance tool genBSDF enables users to generate BSDF data for arbitrary CFS. Prior to genBSDF, BSDF data...... for arbitrary fenestration systems could only be produced using either expensive software or with expensive equipment. genBSDF outputs CFS data in the Window 6 XML file format and so can be used with CFS-enabled software tools to model multi-layered window systems composed of glazing and shading layers...

  7. A discussion of the bi-directional ranking of occurrence-frequency based non-interactive literature method for knowledge discovery

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Yunqiu; GUO; Kelei

    2009-01-01

    Based on the analysis of the existing ranking terminology or subject relevancy of documents methods through an intermediary collection as a catalyst(designated as Group B collection)for the purpose of of non-interactive literature-based discovery,this article proposes a bi-directional document occurrence frequency based ranking method according to the"concurrence theory"and the degree and extent of the subject relevancy.This method explores and further refines the ranking method that is based on the occurrence frequency of the usage of certain terminologies and documents and injects a new insightful perspective of the concurrence of appropriate terminologies/documents in the"low occurrence frequency component"of three non-interactive document collections.A preliminary experiment was conducted to analyze and to test the significance and viability of our newly designed operational method.

  8. The construction and characterization of the bi-directional promoter between pp38 gene and 1.8-kb mRNA transcripts of Marek's disease viruses

    Directory of Open Access Journals (Sweden)

    Ding Jiabo

    2009-11-01

    Full Text Available Abstract Background Marek's disease virus (MDV has a bi-directional promoter between pp38 gene and 1.8-kb mRNA transcripts. By sequencing for the promoters from 8 different strains (CVI988, 814, GA, JM, Md5, G2, RB1B and 648A, it is found, comparing with the other 7 MDV strains, CVI988 has a 5-bp (from -628 to -632 deletion in this region, which caused a Sp1 site destroyed. In order to analysis the activity of the promoter, the complete bi-directional promoters from GA and CVI988 were, respectively, cloned into pCAT-Basic vector in both directions for the recombinants pPGA(pp38-CAT, pPGA(1.8 kb-CAT, pPCVI(pp38-CAT and pPCVI(1.8 kb-CAT. The complete promoter of GA was divided into two single-direction promoters from the replication of MDV genomic DNA, and cloned into pCAT-Basic for pdPGA(pp38-CAT and pdPGA(1.8 kb-CAT as well. The above 6 recombinants were then transfected into chicken embryo fibroblasts (CEFs infected with MDV, and the activity of chloramphenicol acetyltransferase (CAT was measured from the lysed CEFs 48 h post transfection. Results The results showed the activity of the divided promoters was decreased on both directions. In 1.8-kb mRNA direction, it is nearly down to 2.4% (19/781 of the whole promoter, while it keeps 65% (34/52 activity in pp38 direction. The deletion of Sp1 site in CVI988 causes the 20% activity decreased, and has little influence in pp38 direction. Conclusion The present study confirmed their result, and the promoter for the 1.8-kb mRNA transcripts is a much stronger promoter than that in the orientation for pp38.

  9. Bi-directional gene set enrichment and canonical correlation analysis identify key diet-sensitive pathways and biomarkers of metabolic syndrome

    Directory of Open Access Journals (Sweden)

    Gaora Peadar Ó

    2010-10-01

    Full Text Available Abstract Background Currently, a number of bioinformatics methods are available to generate appropriate lists of genes from a microarray experiment. While these lists represent an accurate primary analysis of the data, fewer options exist to contextualise those lists. The development and validation of such methods is crucial to the wider application of microarray technology in the clinical setting. Two key challenges in clinical bioinformatics involve appropriate statistical modelling of dynamic transcriptomic changes, and extraction of clinically relevant meaning from very large datasets. Results Here, we apply an approach to gene set enrichment analysis that allows for detection of bi-directional enrichment within a gene set. Furthermore, we apply canonical correlation analysis and Fisher's exact test, using plasma marker data with known clinical relevance to aid identification of the most important gene and pathway changes in our transcriptomic dataset. After a 28-day dietary intervention with high-CLA beef, a range of plasma markers indicated a marked improvement in the metabolic health of genetically obese mice. Tissue transcriptomic profiles indicated that the effects were most dramatic in liver (1270 genes significantly changed; p Conclusion Bi-directional gene set enrichment analysis more accurately reflects dynamic regulatory behaviour in biochemical pathways, and as such highlighted biologically relevant changes that were not detected using a traditional approach. In such cases where transcriptomic response to treatment is exceptionally large, canonical correlation analysis in conjunction with Fisher's exact test highlights the subset of pathways showing strongest correlation with the clinical markers of interest. In this case, we have identified selenoamino acid metabolism and steroid biosynthesis as key pathways mediating the observed relationship between metabolic health and high-CLA beef. These results indicate that this type of

  10. 基于锂电池化成的新型双向DC/DC拓扑结构研究与建模%Research and Modeling of New Bi-directional DC/DC Topological Structure Based on Lithium Battery

    Institute of Scientific and Technical Information of China (English)

    李少林; 王宜志; 李志斌

    2011-01-01

    A new kind of bi-directional DC/DC topological structure used in the technology of lithium batteries is put for-ward. Adopting two-stage bi-directional DC/DC topological combination ( the half-bridge bi-directional converter and the buck-boost bi-directional converter) , and taking control of buck-boost bi-directional converter by digital signal processor, which can attain the transformation of large voltage differences. The loop simulation of the topological structure of the power circuit can be realized in the environment of Matlab/Simlink. The simulation results show that the converter performance is stahle, and can effectively realize bi-directional transformation between 3 V battery voltage and 400 V bus bar voltage.%提出一种用于锂电池化成技术的新型双向DC/DC拓扑结构.采用两级双向DC/DC拓扑结构,一级使用半桥双向变换器,另一级使用Buck-boost双向变换器,用数字信号处理器对Buck-boost双向变换器进行闭环控制,能实现输入电压和输出电压有较大压差的情况下进行变换.在Matlab/Simlink下对该拓扑结构进行验证.结果表明,该变换器性能稳定,能有效地实现3 V电池电压和400 V母线电压双向变换.

  11. Myths on Bi-direction Communication of Web 2.0 Based Social Networks: Is Social Network Truly Interactive?

    Science.gov (United States)

    2011-03-10

    related to Google News rather than Google Trends. Social network moves faster than conventional media as they directly reflect public opinions . 15...Provide more active monitoring • Monitor Live update • Provide information for impact analysis of public issues/ opinions • Provide early warning and...Emergency Department Triage Data Predicted the 2009 Pandemic H1n1 Waves in Manitoba. Canadian Journal of Public Health-Revue Canadienne De Sante Publique

  12. The effects of SIFT on the reproducibility and biological accuracy of the structural connectome.

    Science.gov (United States)

    Smith, Robert E; Tournier, Jacques-Donald; Calamante, Fernando; Connelly, Alan

    2015-01-01

    Diffusion MRI streamlines tractography is increasingly being used to characterise and assess the structural connectome of the human brain. However, issues pertaining to quantification of structural connectivity using streamlines reconstructions are well-established in the field, and therefore the validity of any conclusions that may be drawn from these analyses remains ambiguous. We recently proposed a post-processing method entitled "SIFT: Spherical-deconvolution Informed Filtering of Tractograms" as a mechanism for reducing the biases in quantitative measures of connectivity introduced by the streamlines reconstruction method. Here, we demonstrate the advantage of this approach in the context of connectomics in three steps. Firstly, we carefully consider the model imposed by the SIFT method, and the implications this has for connectivity quantification. Secondly, we investigate the effects of SIFT on the reproducibility of structural connectome construction. Thirdly, we compare quantitative measures extracted from structural connectomes derived from streamlines tractography, with and without the application of SIFT, to published estimates drawn from post-mortem brain dissection. The combination of these sources of evidence demonstrates the important role the SIFT methodology has for the robust quantification of structural connectivity of the brain using diffusion MRI.

  13. An optimized structure on FPGA of key point description in SIFT algorithm

    Science.gov (United States)

    Xu, Chenyu; Peng, Jinlong; Zhu, En; Zou, Yuxin

    2015-12-01

    SIFT algorithm is one of the most significant and effective algorithms to describe the features of image in the field of image matching. To implement SIFT algorithm to hardware environment is apparently considerable and difficult. In this paper, we mainly discuss the realization of Key Point Description in SIFT algorithm, along with Matching process. In Key Point Description, we have proposed a new method of generating histograms, to avoid the rotation of adjacent regions and insure the rotational invariance. In Matching, we replace conventional Euclidean distance with Hamming distance. The results of the experiments fully prove that the structure we propose is real-time, accurate, and efficient. Future work is still needed to improve its performance in harsher conditions.

  14. A Novel Image Retrieval Based on Visual Words Integration of SIFT and SURF.

    Science.gov (United States)

    Ali, Nouman; Bajwa, Khalid Bashir; Sablatnig, Robert; Chatzichristofis, Savvas A; Iqbal, Zeshan; Rashid, Muhammad; Habib, Hafiz Adnan

    2016-01-01

    With the recent evolution of technology, the number of image archives has increased exponentially. In Content-Based Image Retrieval (CBIR), high-level visual information is represented in the form of low-level features. The semantic gap between the low-level features and the high-level image concepts is an open research problem. In this paper, we present a novel visual words integration of Scale Invariant Feature Transform (SIFT) and Speeded-Up Robust Features (SURF). The two local features representations are selected for image retrieval because SIFT is more robust to the change in scale and rotation, while SURF is robust to changes in illumination. The visual words integration of SIFT and SURF adds the robustness of both features to image retrieval. The qualitative and quantitative comparisons conducted on Corel-1000, Corel-1500, Corel-2000, Oliva and Torralba and Ground Truth image benchmarks demonstrate the effectiveness of the proposed visual words integration.

  15. A Novel Image Retrieval Based on Visual Words Integration of SIFT and SURF.

    Directory of Open Access Journals (Sweden)

    Nouman Ali

    Full Text Available With the recent evolution of technology, the number of image archives has increased exponentially. In Content-Based Image Retrieval (CBIR, high-level visual information is represented in the form of low-level features. The semantic gap between the low-level features and the high-level image concepts is an open research problem. In this paper, we present a novel visual words integration of Scale Invariant Feature Transform (SIFT and Speeded-Up Robust Features (SURF. The two local features representations are selected for image retrieval because SIFT is more robust to the change in scale and rotation, while SURF is robust to changes in illumination. The visual words integration of SIFT and SURF adds the robustness of both features to image retrieval. The qualitative and quantitative comparisons conducted on Corel-1000, Corel-1500, Corel-2000, Oliva and Torralba and Ground Truth image benchmarks demonstrate the effectiveness of the proposed visual words integration.

  16. Multiscale registration of remote sensing image using robust SIFT features in Steerable-Domain

    Directory of Open Access Journals (Sweden)

    Xiangzeng Liu

    2011-12-01

    Full Text Available This paper proposes a multiscale registration technique using robust Scale Invariant Feature Transform (SIFT features in Steerable-Domain, which can deal with the large variations of scale, rotation and illumination between images. First, a new robust SIFT descriptor is presented, which is invariant under affine transformation. Then, an adaptive similarity measure is developed according to the robust SIFT descriptor and the adaptive normalized cross correlation of feature point’s neighborhood. Finally, the corresponding feature points can be determined by the adaptive similarity measure in Steerable-Domain of the two input images, and the final refined transformation parameters determined by using gradual optimization are adopted to achieve the registration results. Quantitative comparisons of our algorithm with the related methods show a significant improvement in the presence of large scale, rotation changes, and illumination contrast. The effectiveness of the proposed method is demonstrated by the experimental results.

  17. 一种改进的基于BiDirectional体制的MISO-SAR系统%Improved MISO-SAR System Based on BiDirectional Imaging

    Institute of Scientific and Technical Information of China (English)

    蒋海; 宋红军

    2015-01-01

    In 2012, the German Aerospace Center (DLR.) proposed a BiDirectional mode that can achieve several seconds of repeated time lags by single star and single flight. Its basic principle includes the generation of a double-beam antenna pattern by electronic beam steering and simultaneous emission of two pulses that irradiate the front and back imaging area. The two pulses, which are simultaneously received will be separated by band-pass filtering in the Doppler domain and imaged, respectively. This paper presents an improved Multi Input Single Output (MISO)-SAR system based on the BiDirectional mode which converts the traditional simultaneous dual beam emitting and receiving into time-division emitting and simultaneous receiving, respectively. This results in an improved emitting antenna pattern owning to the suppression of the Azimuth Ambiguity to Signal Ratio (AASR). The current paper describes the spectrum separation effects, AASR analysis, and the system design process. Therefore, to confirm effectiveness, point target 1-D and 2-D simulation results are compared before and after the improvement. Furthermore, the BiDirectional and other short-term repeated SAR modes are compared.%BiDirectional体制是德宇航在2012年提出的一种通过单星单次飞行实现秒级重访的新体制,基本原理是利用相控阵电扫描方式生成双波束天线方向图,同时发射两个脉冲照射方位向前后两块成像区域,将同时接收到的脉冲在多普勒域进行带通滤波分离,并分别成像。该文介绍了一种改进的基于BiDirectional体制的多发单收(Multi Input Single Output, MISO)SAR系统,将传统的双波束同发同收改进为分时先后发射和同时接收,利用发射时较优的方向图抑制方位模糊(AASR),获得了较好的效果。文中给出了频谱分离效果、AASR分析和系统设计流程,给出了改进前后的点目标1维和2维成像结果对比,证明了该改进的有效性,最后

  18. SIFT - A preliminary evaluation. [Software Implemented Fault Tolerant computer for aircraft control

    Science.gov (United States)

    Palumbo, D. L.; Butler, R. W.

    1983-01-01

    This paper presents the results of a performance evaluation of the SIFT computer system conducted in the NASA AIRLAB facility. The essential system functions are described and compared to both earlier design proposals and subsequent design improvements. The functions supporting fault tolerance are found to consume significant computing resources. With SIFT's specimen task load, scheduled at a 30-Hz rate, the executive tasks such as reconfiguration, clock synchronization and interactive consistency, require 55 percent of the available task slots. Other system overhead (e.g., voting and scheduling) use an average of 50 percent of each remaining task slot.

  19. Remote sensing image registration approach based on a retrofitted SIFT algorithm and Lissajous-curve trajectories.

    Science.gov (United States)

    Song, Zhi-li; Li, Sheng; George, Thomas F

    2010-01-18

    Through retrofitting the descriptor of a scale-invariant feature transform (SIFT) and developing a new similarity measure function based on trajectories generated from Lissajous curves, a new remote sensing image registration approach is constructed, which is more robust and accurate than prior approaches. In complex cases where the correct rate of feature matching is below 20%, the retrofitted SIFT descriptor improves the correct rate to nearly 100%. Mostly, the similarity measure function makes it possible to quantitatively analyze the temporary change of the same geographic position.

  20. An Optimized Structure on FPGA of Key Point Detection in SIFT Algorithm

    Directory of Open Access Journals (Sweden)

    Xu Chenyu

    2016-01-01

    Full Text Available SIFT algorithm is the most efficient and powerful algorithm to describe the features of images and it has been applied in many fields. In this paper, we propose an optimized method to realize the hardware implementation of the SIFT algorithm. We mainly discuss the structure of Data Generation here. A pipeline architecture is introduced to accelerate this optimized system. Parameters’ setting and approximation’s controlling in different image qualities and hardware resources are the focus of this paper. The results of experiments fully prove that this structure is real-time and effective, and provide consultative opinion to meet the different situations.

  1. 基于SIFT-SUSAN算法的零件图像特征提取研究%Parts image feature extraction based on SIFT-SUSAN algorithm

    Institute of Scientific and Technical Information of China (English)

    张丛; 李永刚; 罗陆锋

    2014-01-01

    SIFT-SUSAN算法应用在零件图像的特征提取上,检测图像的特征极值点。首先对采集的图像进行均值滤波和Laplace锐化预处理,以此增强图像的边缘响应;利用高斯卷积和高斯差分建立尺度空间域;再利用SIFT算法提取空间极值点,并引入SUSAN算子检测空间角点;计算两种特征点的位置,生成特征描述子,实现零件图像的匹配。通过对垫片、螺母和轴承盖零件分别采用SIFT算法和SIFT-SUSAN算法进行对比试验,实验表明:SIFT-SUSAN算法结合了图像区域和边缘角点特征,得到更多的匹配点,提高了图片匹配的正确率。

  2. Quantification by SIFT-MS of acetaldehyde released by lung cells in a 3D model.

    Science.gov (United States)

    Rutter, Abigail V; Chippendale, Thomas W E; Yang, Ying; Španěl, Patrik; Smith, David; Sulé-Suso, Josep

    2013-01-07

    Our previous studies have shown that both lung cancer cells and non-malignant lung cells release acetaldehyde in vitro. However, data from other laboratories have produced conflicting results. Furthermore, all these studies have been carried out in 2D models which are less physiological cell growth systems when compared to 3D models. Therefore, we have carried out further work on the release of acetaldehyde by lung cells in 3D collagen hydrogels. Lung cancer cells CALU-1 and non-malignant lung cells NL20 were seeded in these hydrogels at different cell concentrations and the release of acetaldehyde was measured with the Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) technique. The data obtained showed that the amount of acetaldehyde released by both cell types grown in a 3D model is higher when compared to that of the same cells grown in 2D models. More importantly, acetaldehyde from the headspace of lung cancer cells could be measured even at a low cell concentration (10(5) cells per hydrogel). The differential of acetaldehyde release could be, depending on the cell concentration, more than 3 fold higher for cancer cells when compared to non-malignant lung cells. This pilot study is the first to study acetaldehyde emission from albeit only two cell types cultured in 3D scaffolds. Clearly, from such limited data the behaviour of other cell types and of tumour cells in vivo cannot be predicted with confidence. Nevertheless, this work represents another step in the search for volatile biomarkers of tumour cells, the ultimate goal of which is to exploit volatile compounds in exhaled breath and other biological fluids as biomarkers of tumours in vivo.

  3. Increase of methanol in exhaled breath quantified by SIFT-MS following aspartame ingestion.

    Science.gov (United States)

    Španěl, Patrik; Dryahina, Kseniya; Vicherková, Petra; Smith, David

    2015-11-19

    Aspartame, methyl-L-α-aspartyl-L-phenylalaninate, is used worldwide as a sweetener in foods and drinks and is considered to be safe at an acceptable daily intake (ADI) of 40 mg per kg of body weight. This compound is completely hydrolyzed in the gastrointestinal tract to aspartic acid, phenylalanine and methanol, each being toxic at high levels. The objective of the present study was to quantify the volatile methanol component in the exhaled breath of ten healthy volunteers following the ingestion of a single ADI dose of aspartame. Direct on-line measurements of methanol concentration were made in the mouth and nose breath exhalations using selected ion flow tube mass spectrometry, SIFT-MS, several times before aspartame ingestion in order to establish individual pre-dose (baseline) levels and then during two hours post-ingestion to track their initial increase and subsequent decrease. The results show that breath methanol concentrations increased in all volunteers by 1082   ±   205 parts-per-billion by volume (ppbv) from their pre-ingestion values, which ranged from 193 to 436 ppbv to peak values ranging from 981-1622 ppbv, from which they slowly decreased. These observations agree quantitatively with a predicted increase of 1030 ppbv estimated using a one-compartment model of uniform dilution of the methanol generated from a known amount of aspartame throughout the total body water (including blood). In summary, an ADI dose of aspartame leads to a 3-6 fold increase of blood methanol concentration above the individual baseline values.

  4. A 30 Gb/s full-duplex bi-directional transmission optical wireless-over fiber integration system at W-band.

    Science.gov (United States)

    Tang, Chanjuan; Yu, Jianjun; Li, Xinying; Chi, Nan; Xiao, Jiangnan; Tian, Yumin; Zhang, Junwen

    2014-01-13

    We propose and experimentally demonstrate a full-duplex bi-directional transmission optical wireless-over fiber integration system at W-band (75-100 GHz) with the speed up to 15 Gb/s for both 95.4 GHz link and 88.6 GHz link for the first time. The generation of millimeter-wave (mm-wave) wireless signal is based on the photonic technique by heterodyne mixing of an optical quadrature-phase-shift-keying (QPSK) signal with a free-running light at different wavelength. After 20 km fiber transmission, up to 30 Gb/s mm-wave signal is delivered over 2 m wireless link, and then converted to the optical signal for another 20 km fiber transmission. At the wireless receiver, coherent detection and advanced digital signal processing (DSP) are introduced to improve receiver sensitivity and system performance. With the OSNR of 15 dB, the bit error ratios (BERs) for 10 Gb/s signal transmission at 95.4 GHz and 88.6 GHz are below the forward-error-correction (FEC) threshold of 3.8 × 10(-3) whether post filter is used or not, while the BER for 15 Gb/s QPSK signal employing post filter in the link of 95.4 GHz is 2.9 × 10(-3).

  5. SURFATM-NH3: a model combining the surface energy balance and bi-directional exchanges of ammonia applied at the field scale

    Science.gov (United States)

    Personne, E.; Loubet, B.; Herrmann, B.; Mattsson, M.; Schjoerring, J. K.; Nemitz, E.; Sutton, M. A.; Cellier, P.

    2009-08-01

    A new biophysical model SURFATM-NH3, simulating the ammonia (NH3) exchange between terrestrial ecosystems and the atmosphere is presented. SURFATM-NH3 consists of two coupled models: (i) an energy budget model and (ii) a pollutant exchange model, which distinguish the soil and plant exchange processes. The model describes the exchanges in terms of adsorption to leaf cuticles and bi-directional transport through leaf stomata and soil. The results of the model are compared with the flux measurements over grassland during the GRAMINAE Integrated Experiment at Braunschweig, Germany. The dataset of GRAMINAE allows the model to be tested in various meteorological and agronomic conditions: prior to cutting, after cutting and then after the application of mineral fertilizer. The whole comparison shows close agreement between model and measurements for energy budget and ammonia fluxes. The major controls on the ground and plant emission potential are the physicochemical parameters for liquid-gas exchanges which are integrated in the compensation points for live leaves, litter and the soil surface. Modelled fluxes are highly sensitive to soil and plant surface temperatures, highlighting the importance of accurate estimates of these terms. The model suggests that the net flux depends not only on the foliar (stomatal) compensation point but also that of leaf litter. SURFATM-NH3 represents a comprehensive approach to studying pollutant exchanges and its link with plant and soil functioning. It also provides a simplified generalised approach (SVAT model) applicable for atmospheric transport models.

  6. Priming in the Type I-F CRISPR-Cas system triggers strand-independent spacer acquisition, bi-directionally from the primed protospacer.

    Science.gov (United States)

    Richter, Corinna; Dy, Ron L; McKenzie, Rebecca E; Watson, Bridget N J; Taylor, Corinda; Chang, James T; McNeil, Matthew B; Staals, Raymond H J; Fineran, Peter C

    2014-07-01

    Clustered regularly interspaced short palindromic repeats (CRISPR), in combination with CRISPR associated (cas) genes, constitute CRISPR-Cas bacterial adaptive immune systems. To generate immunity, these systems acquire short sequences of nucleic acids from foreign invaders and incorporate these into their CRISPR arrays as spacers. This adaptation process is the least characterized step in CRISPR-Cas immunity. Here, we used Pectobacterium atrosepticum to investigate adaptation in Type I-F CRISPR-Cas systems. Pre-existing spacers that matched plasmids stimulated hyperactive primed acquisition and resulted in the incorporation of up to nine new spacers across all three native CRISPR arrays. Endogenous expression of the cas genes was sufficient, yet required, for priming. The new spacers inhibited conjugation and transformation, and interference was enhanced with increasing numbers of new spacers. We analyzed ∼ 350 new spacers acquired in priming events and identified a 5'-protospacer-GG-3' protospacer adjacent motif. In contrast to priming in Type I-E systems, new spacers matched either plasmid strand and a biased distribution, including clustering near the primed protospacer, suggested a bi-directional translocation model for the Cas1:Cas2-3 adaptation machinery. Taken together these results indicate priming adaptation occurs in different CRISPR-Cas systems, that it can be highly active in wild-type strains and that the underlying mechanisms vary.

  7. Dense central office solution for point-to-point fibre access including a novel compact dual bi-directional fibre optical transceiver

    Science.gov (United States)

    Arvidsson, Gunnar; Junique, Stéphane; Persson, Karl-Åke; Sundberg, Erland

    2006-07-01

    The centralized Point-to-Point fibre access approach with a dedicated single mode optical fibre link connecting each customer to a Central Office (CO) has advantages regarding future-proofness, security, and simple and low-cost optical links and transceivers. The potential bottleneck in handling the large number of optical fibres that need to be terminated in the CO, and combined with optoelectronic components, has been studied within the IST 6th Framework Programme integrated project MUSE. The key parts in the CO are the passive cabinet where customer fibres are accessible through fibre connectors in the Optical Distribution Frame (ODF), and the active cabinet with switching equipment and optical transceivers. For the passive cabinet we conclude, that the most efficient solution is that each connection from the active cabinet to a customer passes only one ODF, and that small form factor connectors are used. For the active cabinet we have demonstrated the feasibility of an SFF-size module containing two bi-directional transceiver units by building and successfully testing a prototype, increasing the customer port density by a factor of two compared to commercial transceivers. The power consumption, which impacts power supply, cooling and cost, has been analyzed, and we propose measures to significantly decrease the power consumption.

  8. Redundantly piezo-actuated XYθ z compliant mechanism for nano-positioning featuring simple kinematics, bi-directional motion and enlarged workspace

    Science.gov (United States)

    Zhu, Wu-Le; Zhu, Zhiwei; To, Suet; Liu, Qiang; Ju, Bing-Feng; Zhou, Xiaoqin

    2016-12-01

    This paper presents a novel redundantly piezo-actuated three-degree-of-freedom XYθ z compliant mechanism for nano-positioning, driven by four mirror-symmetrically configured piezoelectric actuators (PEAs). By means of differential motion principle, linearized kinematics and physically bi-directional motions in all the three directions are achieved. Meanwhile, the decoupled delivering of three-directional independent motions at the output end is accessible, and the essential parallel and mirror symmetric configuration guarantees large output stiffness, high natural frequencies, high accuracy as well as high structural compactness of the mechanism. Accurate kinematics analysis with consideration of input coupling indicates that the proposed redundantly actuated compliant mechanism can generate three-dimensional (3D) symmetric polyhedral workspace envelope with enlarged reachable workspace, as compared with the most common parallel XYθ z mechanism driven by three PEAs. Keeping a high consistence with both analytical and numerical models, the experimental results show the working ranges of ±6.21 μm and ±12.41 μm in X- and Y-directions, and that of ±873.2 μrad in θ z-direction with nano-positioning capability can be realized. The superior performances and easily achievable structure well facilitate practical applications of the proposed XYθ z compliant mechanism in nano-positioning systems.

  9. Fingerprint Identification Using SIFT-Based Minutia Descriptors and Improved All Descriptor-Pair Matching

    Directory of Open Access Journals (Sweden)

    Jiuqiang Han

    2013-03-01

    Full Text Available The performance of conventional minutiae-based fingerprint authentication algorithms degrades significantly when dealing with low quality fingerprints with lots of cuts or scratches. A similar degradation of the minutiae-based algorithms is observed when small overlapping areas appear because of the quite narrow width of the sensors. Based on the detection of minutiae, Scale Invariant Feature Transformation (SIFT descriptors are employed to fulfill verification tasks in the above difficult scenarios. However, the original SIFT algorithm is not suitable for fingerprint because of: (1 the similar patterns of parallel ridges; and (2 high computational resource consumption. To enhance the efficiency and effectiveness of the algorithm for fingerprint verification, we propose a SIFT-based Minutia Descriptor (SMD to improve the SIFT algorithm through image processing, descriptor extraction and matcher. A two-step fast matcher, named improved All Descriptor-Pair Matching (iADM, is also proposed to implement the 1:N verifications in real-time. Fingerprint Identification using SMD and iADM (FISiA achieved a significant improvement with respect to accuracy in representative databases compared with the conventional minutiae-based method. The speed of FISiA also can meet real-time requirements.

  10. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Science.gov (United States)

    2010-10-01

    ... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or sifting of radioactive materials. (a) In case of fire, collision, or breakage involving any shipment of radioactive materials, other than materials of low specific activity, the radioactive materials must...

  11. Strain field measurements around notches using SIFT features and meshless methods.

    Science.gov (United States)

    Gonzáles, Giancarlo; Meggiolaro, Marco

    2015-05-10

    This work proposes a hybrid experimental-numerical technique with the aim to improve strain measurements at stress concentration regions. The novel technique is performed employing the computer vision scale invariant feature transform (SIFT) algorithm and meshless methods, here termed SIFT-meshless. The SIFT is applied to perform feature points matching in two images of the specimen surface at different stages of mechanical deformation. The output data are provided as a set of displacement measurements by tracking matched feature points. This information is then used to model displacement and strain field on the surface by means of a meshless formulation based on the moving least squares approximation. By applying the proposed SIFT-meshless method, the strain distribution around a semicircular notch in a plate under bending load was investigated. The experimental results were compared with those obtained by a digital image correlation technique based on a subset approach and to simulations from finite element analysis software. The experimental results demonstrated that the present method is capable of performing reliable strain measurements at distances close to the notch where the peak strain value is expected, even in the presence of high strain gradients.

  12. SIFT-MS analysis of Iberian hams from pigs reared under different conditions.

    Science.gov (United States)

    Carrapiso, Ana I; Noseda, Bert; García, Carmen; Reina, Raquel; Sánchez Del Pulgar, José; Devlieghere, Frank

    2015-06-01

    The aim of this study was to investigate the usefulness of a Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) equipment to tentatively quantify relevant volatile compounds of dry-cured Iberian ham, and to differentiate Iberian hams from pigs reared at four different conditions yielding different commercial grades. The SIFT-MS analysis allowed the rapid quantification of 39 Iberian ham volatile compounds, 16 of them being significantly affected by the rearing conditions of pigs. The full spectra SIFT-MS data allowed the correct classification of 79.2% of hams according to diet, which is a smaller percentage than that obtained using intramuscular fatty acid data (95.8%) obtained by using a gas chromatograph-flame ionization detector after lipid extraction and transesterification. Therefore, the SIFT-MS analysis would be a rapid tool to tentatively quantify some relevant volatile compounds, and also would provide a rapid but rough classification of Iberian ham according to the rearing conditions of pigs.

  13. Robot path Planning Using  SIFT and Sonar Sensor Fusion

    DEFF Research Database (Denmark)

    Plascencia, Alfredo; Raposo, Hector

    2007-01-01

    and evidential grid maps, respectively. The approach is illustrated using actual measurements from a laboratory robot. The sensory information is obtained from a sonar array and the Scale Invariant Feature Transform (SIFT) algorithm. Finally, the resulting two evidential maps based on Bayes and Dempster theories...

  14. SIFT-OUT: Training for Systems Change in Early Intervention. Final Report.

    Science.gov (United States)

    Winton, Pamela J.; Catlett, Camille

    This report summarizes the activities of the SIFT-OUT program, a federally funded project designed to prepare teams of university faculty, family members, practitioners, and agency representatives from six states, to serve as leaders in providing early intervention training in their states. A total of 166 state-level early intervention leaders…

  15. Possibility Study of Scale Invariant Feature Transform (SIFT) Algorithm Application to Spine Magnetic Resonance Imaging.

    Science.gov (United States)

    Lee, Dong-Hoon; Lee, Do-Wan; Han, Bong-Soo

    2016-01-01

    The purpose of this study is an application of scale invariant feature transform (SIFT) algorithm to stitch the cervical-thoracic-lumbar (C-T-L) spine magnetic resonance (MR) images to provide a view of the entire spine in a single image. All MR images were acquired with fast spin echo (FSE) pulse sequence using two MR scanners (1.5 T and 3.0 T). The stitching procedures for each part of spine MR image were performed and implemented on a graphic user interface (GUI) configuration. Moreover, the stitching process is performed in two categories; manual point-to-point (mPTP) selection that performed by user specified corresponding matching points, and automated point-to-point (aPTP) selection that performed by SIFT algorithm. The stitched images using SIFT algorithm showed fine registered results and quantitatively acquired values also indicated little errors compared with commercially mounted stitching algorithm in MRI systems. Our study presented a preliminary validation of the SIFT algorithm application to MRI spine images, and the results indicated that the proposed approach can be performed well for the improvement of diagnosis. We believe that our approach can be helpful for the clinical application and extension of other medical imaging modalities for image stitching.

  16. SIFT - Multiprocessor architecture for Software Implemented Fault Tolerance flight control and avionics computers

    Science.gov (United States)

    Forman, P.; Moses, K.

    1979-01-01

    A brief description of a SIFT (Software Implemented Fault Tolerance) Flight Control Computer with emphasis on implementation is presented. A multiprocessor system that relies on software-implemented fault detection and reconfiguration algorithms is described. A high level reliability and fault tolerance is achieved by the replication of computing tasks among processing units.

  17. An improved SIFT algorithm in the application of close-range Stereo image matching

    Science.gov (United States)

    Zhang, Xuehua; Wang, Xiaoqing; Yuan, Xiaoxiang; Wang, Shumin

    2016-11-01

    As unmanned aerial vehicle (UAV) remote sensing is applied in small area aerial photogrammetry surveying, disaster monitoring and emergency command, 3D urban construction and other fields, the image processing of UAV has become a hot topic in current research. The precise matching of UAV image is a key problem, which affects the subsequent processing precision directly, such as 3D reconstruction and automatic aerial triangulation, etc. At present, SIFT (Scale Invariant Feature Transform) algorithm proposed by DAVID G. LOWE as the main method is, is widely used in image matching, since its strong stability to image rotation, shift, scaling, and the change of illumination conditions. It has been successfully applied in target recognition, SFM (Structure from Motion), and many other fields. SIFT algorithm needs the colour images to be converted into grayscale images, detects extremum points under different scales and uses neighbourhood pixels to generate descriptor. As we all know that UAV images with rich colour information, the SIFT algorithm improved through combining with the image colour information in this paper, the experiments are conducted from matching efficiency and accuracy compared with the original SIFT algorithm. The results show that the method which proposed in this paper decreases on the efficiency, but is improved on the precision and provides a basis choice for matching method.

  18. Color Image Secret Watermarking Erase and Write Algorithm Based on SIFT

    Science.gov (United States)

    Qu, Jubao

    The use of adaptive characteristics of SIFT, image features, the implementation of the write, erase operations on Extraction and color image hidden watermarking. From the experimental results, this algorithm has better imperceptibility and at the same time, is robust against geometric attacks and common signal processing.

  19. Fingerprint identification using SIFT-based minutia descriptors and improved all descriptor-pair matching.

    Science.gov (United States)

    Zhou, Ru; Zhong, Dexing; Han, Jiuqiang

    2013-03-06

    The performance of conventional minutiae-based fingerprint authentication algorithms degrades significantly when dealing with low quality fingerprints with lots of cuts or scratches. A similar degradation of the minutiae-based algorithms is observed when small overlapping areas appear because of the quite narrow width of the sensors. Based on the detection of minutiae, Scale Invariant Feature Transformation (SIFT) descriptors are employed to fulfill verification tasks in the above difficult scenarios. However, the original SIFT algorithm is not suitable for fingerprint because of: (1) the similar patterns of parallel ridges; and (2) high computational resource consumption. To enhance the efficiency and effectiveness of the algorithm for fingerprint verification, we propose a SIFT-based Minutia Descriptor (SMD) to improve the SIFT algorithm through image processing, descriptor extraction and matcher. A two-step fast matcher, named improved All Descriptor-Pair Matching (iADM), is also proposed to implement the 1:N verifications in real-time. Fingerprint Identification using SMD and iADM (FISiA) achieved a significant improvement with respect to accuracy in representative databases compared with the conventional minutiae-based method. The speed of FISiA also can meet real-time requirements.

  20. CB1 receptor activation in the rat paraventricular nucleus induces bi-directional cardiovascular effects via modification of glutamatergic and GABAergic neurotransmission.

    Science.gov (United States)

    Grzęda, Emilia; Schlicker, Eberhard; Toczek, Marek; Zalewska, Iwona; Baranowska-Kuczko, Marta; Malinowska, Barbara

    2017-01-01

    We have shown previously that the cannabinoid receptor agonist CP55940 microinjected into the paraventricular nucleus of the hypothalamus (PVN) of urethane-anaesthetized rats induces depressor and pressor cardiovascular effects in the absence and presence of the CB1 antagonist AM251, respectively. The aim of our study was to examine whether the hypotension and/or hypertension induced by CP55940 given into the PVN results from its influence on glutamatergic and GABAergic neurotransmission. CP55940 was microinjected into the PVN of urethane-anaesthetized rats twice (S1 and S2, 20 min apart). Antagonists of the following receptors, NMDA (MK801), β2-adrenergic (ICI118551), thromboxane A2-TP (SQ29548), angiotensin II-AT1 (losartan) or GABAA (bicuculline), or the NO synthase inhibitor L-NAME were administered intravenously 5 min before S2 alone or together with AM251. The CP55940-induced hypotension was reversed into a pressor response by AM251, bicuculline and L-NAME, but not by the other antagonists. The CP55940-induced pressor effect examined in the presence of AM251 was completely reversed by losartan, reduced by about 50-60 % by MK801, ICI118551 and SQ29548, prevented by bilateral adrenalectomy but not modified by bicuculline and L-NAME. Parallel, but smaller, changes in heart rate accompanied the changes in blood pressure. The bi-directional CB1 receptor-mediated cardiovascular effects of cannabinoids microinjected into the PVN of anaesthetized rats depend on stimulatory glutamatergic and inhibitory GABAergic inputs to the sympathetic tone; the glutamatergic input is related to AT1, TP and β2-adrenergic receptors and catecholamine release from the adrenal medulla whereas the GABAergic input is reinforced by NO.

  1. Threshold-Opportunistic Relaying Strategy Based on Bi-Directional Flows Network%基于双向流的门限机会中继策略

    Institute of Scientific and Technical Information of China (English)

    胡同森; 张茜; 田贤忠

    2011-01-01

    We research a bi-directional traffic flows network which two nodes are in each signal coverage area's in this article.Selecting optimum relaying using opportunistic relaying strategy based on instantaneous channel state information, then judging whether needs optimum relaying participates in the cooperation according to the threshold value.Don't need relay for transmission when the direct-transmission channel state is bigger than the threshold value;whereas sources and optimum relaying cooperate together.Comparing with direct transmission model, this strategy improves the network throughput, enhances the performance against fading, and reduces system symbol-error-rate effectively in high signal-to-noise ratio.%对两节点在彼此覆盖范围内的双向传输流模型进行研究.用瞬时链路状态信息的机会中继策略,选择出最佳中继节点,然后根据门限值来判断是否需要最佳中继参与协作,当两节点直连链路状态大于门限值时,节点间直接交互信息,无需中继节点的协助;反之,信源和最佳中继共同协作参与传输.相比直接传输模型,本策略提高网络吞吐量的同时,增大了系统的分集增益,有效的提高了系统的抗衰落性能,并在信噪比高时有效降低系统误码率.

  2. Bi-directional induction of matrix metalloproteinase-9 and tissue inhibitor of matrix metalloproteinase-1 during T lymphoma/endothelial cell contact: implication of ICAM-1.

    Science.gov (United States)

    Aoudjit, F; Potworowski, E F; St-Pierre, Y

    1998-03-15

    The mechanisms that lead to the expression of matrix metalloproteinases (MMP) and tissue inhibitors of MMP (TIMPs) during the invasive process of normal and transformed T cells remain largely unknown. Since vascular cells form a dynamic tissue capable of responding to local stimuli and activating cells through the expression of cytokine receptors and specific cell adhesion molecules, we hypothesized that the firm adhesion of T lymphoma cells to endothelial cells is a critical event in the local production of MMP and TIMP. In the present work, we show that adhesion of lymphoma cells to endothelial cells induced a transient and reciprocal de novo expression of MMP-9 mRNA and enzymatic activity by both cell types. Up-regulation of MMP-9 in T lymphoma cells was concomitant to that of TIMP-1, and required direct contact with endothelial cells. Induction of MMP-9, but not of TIMP-1, was blocked by anti-LFA-1 and anti-intercellular adhesion molecule-1 Abs, indicating that induction of MMP-9 and TIMP-1 in lymphoma cells required direct, yet distinct, intercellular contact. In contrast, the induction of MMP-9 in endothelial cells by T lymphoma cells did not necessitate direct contact and could be achieved by exposure to IL-1 and TNF, or to the supernatant of T lymphoma cell culture. Together, these results demonstrate that firm adhesion of T lymphoma cells to endothelial cells participates in the production of MMP-9 in both cell types through bi-directional signaling pathways, and identify intercellular adhesion molecule-1/LFA-1 as a key interaction in the up-regulation of MMP-9 in T lymphoma cells.

  3. The Matching Research for Bi-Directional-Servo Central Parking Brake%某越野车双向自增力中央驻车制动器的匹配

    Institute of Scientific and Technical Information of China (English)

    薛琼; 叶晓明; 侯鹏伟; 陈智磊

    2013-01-01

    双向自增力鼓式制动器因其效能因数高,在越野车和轻型卡车上作为中央驻车制动器应用较多。就双向自增力中央制动器在开发过程中的几项设计要点进行了详述,解析了自增力鼓式驻车制动器效能因数的计算方法,并通过理论计算和试验对比,验证了方法的准确性。同时,分析了摩擦系数的选择方法,对制动间隙的设计和控制进行了研究。%Bi-directional-servo drum brakes has been used on off-road trucks and light trucks commonly as central parking brake because of its high efficiency factor. Several designing points of the development for bi-directional-servo parking brake have been detailed in this paper, it analyzing the calculation methods of efficient factor for bi-directional-servo parking brake and having been proved the correctness through comparing between theoretical calculations value and test value, analyzing the method of choosing value for friction coefficient and also researching how to designing and controlling brake clearance.

  4. Stepwise Information-Filtering Tool (SIFT): A method for using risk assessment metadata in a nontraditional way.

    Science.gov (United States)

    Beasley, Amy; Belanger, Scott E; Otter, Ryan R

    2015-06-01

    Tools exist to evaluate large ecotoxicity databases for risk assessment purposes, but these tools are less useful for alternative analytical purposes. In the present study, the authors developed the Stepwise Information-Filtering Tool (SIFT), a strategic method to select relevant, reliable data from a large ecotoxicity database; demonstrated utility in a case study of chronic toxicity data for statistical endpoint comparison purposes; and evaluated SIFT by comparison with 2 existing data evaluation methods.

  5. SIFT-MS and FA-MS methods for ambient gas phase analysis: developments and applications in the UK.

    Science.gov (United States)

    Smith, David; Španěl, Patrik

    2015-04-21

    Selected ion flow tube mass spectrometry, SIFT-MS, a relatively new gas/vapour phase analytical method, is derived from the much earlier selected ion flow tube, SIFT, used for the study of gas phase ion-molecule reactions. Both the SIFT and SIFT-MS techniques were conceived and developed in the UK, the former at Birmingham University, the latter at Keele University along with the complementary flowing afterglow mass spectrometry, FA-MS, technique. The focus of this short review is largely to describe the origins, developments and, most importantly, the unique features of SIFT-MS as an analytical tool for ambient analysis and to indicate its growing use to analyse humid air, especially exhaled breath, its unique place as a on-line, real time analytical method and its growing use and applications as a non-invasive diagnostic in clinical diagnosis and therapeutic monitoring, principally within several UK universities and hospitals, and briefly in the wider world. A few case studies are outlined that show the potential of SIFT-MS and FA-MS in the detection and quantification of metabolites in exhaled breath as a step towards recognising pathophysiology indicative of disease and the presence of bacterial and fungal infection of the airways and lungs. Particular cases include the detection of Pseudomonas aeruginosa infection of the airways of patients with cystic fibrosis (SIFT-MS) and the measurement of total body water in patients with chronic kidney disease (FA-MS). The growing exploitation of SIFT-MS in other areas of research and commerce are briefly listed to show the wide utility of this unique UK-developed analytical method, and future prospects and developments are alluded to.

  6. 基于改进Canny特征点的SIFT算法%Improved SIFT algorithm based on Canny feature points

    Institute of Scientific and Technical Information of China (English)

    杨秋菊; 肖雪梅

    2011-01-01

    After the analysis of traditional SIFT algorithm, a new SIFT algorithm based on improving the Canny feature points is proposed. The algorithm firstly detects out candidate keypoints by SIFT algorithm, then finds out the edge points of image using Canny algorithm. It would remove some candidate keypoints by the analysis whether the coordinates are equal between candidate keypoints and edge points. The experimental results show that the improved SIFT algorithm can effectively remove the edge response points, further improve the ability of anti-noise for SIFT features, and display a more stability than the traditional SIFT algorithm.%在分析了传统SIFT算法的基础上,提出了一种基于改进Canny特征点的SIFT算法.该方法先用SIFT算法检测出候选关键点,再利用Canny边缘检测算法检测出图像的边缘点,通过比较生成的候选关键点和边缘点的坐标是否相等,从而判断是否去除候选关键点.实验结果表明,与传统SIFT算法比较,该方法可以有效地去除DOG算子生成的边缘响应点,进一步提高SIFT特征点的抗噪声能力,增强SIFT算法的稳定性.

  7. Construction of recombinant Marek's disease virus (rMDV co-expressing AIV-H9N2-NA and NDV-F genes under control of MDV's own bi-directional promoter.

    Directory of Open Access Journals (Sweden)

    Zhenjie Zhang

    Full Text Available To qualitatively analyze and evaluate a bi-directional promoter transcriptional function in both transient and transgenic systems, several different plasmids were constructed and recombinant MDV type 1 strain GX0101 was developed to co-express a Neuraminidase (NA gene from Avian Influenza Virus H9N2 strain and a Fusion (F gene from the Newcastle disease virus (NDV. The two foreign genes, NDV-F gene and AIV-NA gene, were inserted in the plasmid driven in each direction by the bi-directional promoter. To test whether the expression of pp38/pp24 heterodimers are the required activators for the expression of the foreign genes, the recombinant plasmid pPpp38-NA/1.8kb-F containing expression cassette for the two foreign genes was co-transfected with a pp38/pp24 expression plasmid, pBud-pp38-pp24, in chicken embryo fibroblast (CEF cells. Alternatively, plasmid pPpp38-NA/1.8kb-F was transfected in GX0101-infected CEFs where the viral endogenous pp38/pp24 were expressed via virus infection. The expression of both foreign genes was activated by pp38/pp24 dimers either via virus infection, or co-expression. The CEFs transfected with pPpp38-NA/1.8kb-F alone had no expression. We chose to insert the expression cassette of Ppp38-NA/1.8kb-F in the non-essential region of GX0101ΔMeq US2 gene, and formed a new rMDV named MZC13NA/F through homologous recombination. Indirect fluorescence antibody (IFA test, ELISA and Western blot analyses indicated that F and NA genes were expressed simultaneously under control of the bi-directional promoter, but in opposite directions. The data also indicated the activity of the promoter in the 1.8-kb mRNA transcript direction was higher than that in the direction for the pp38 gene. The expression of pp38/pp24 dimers either via co-tranfection of the pBud-pp38-pp24 plasmid, or by GX0101 virus infection were critical to activate the bi-directional promoter for expression of two foreign genes in both directions. Therefore, the

  8. A SIFT Algorithm for Bistatic SAR Imaging in Spaceborne Constant-offset Configuration (in English

    Directory of Open Access Journals (Sweden)

    Chen Shi-chao

    2013-03-01

    Full Text Available Focusing on the problem of the space-variance of the range cell migration term for bistatic Synthetic Aperture Radar (SAR, a Scaled Inverse Fourier Transform (SIFT based imaging algorithm for constant-offset configuration bistatic SAR data processing is proposed in this article. Range cell migration correction is realized through two times phase multiplies and one time convolution operation. Since the imaging algorithm is based on an exact precise spectrum which is deduced from the Geometry-Based Formula (GBF algorithm, the proposed algorithm can handle the bistatic SAR data which are obtained with a large baseline to ratio. The advantages and effectiveness of the proposed imaging method have been verified by simulated and comparable experiments. Moreover, unlike the other scaling imaging algorithms which are dependent on the frequency modulated characteristics of the signal, the SIFT imaging algorithm is also suitable for phase-coded signal, which has a wider application areas.

  9. ALPHABET RECOGNITION OF AMERICAN SIGN LANGUAGE: A HAND GESTURE RECOGNITION APPROACH USING SIFT ALGORITHM

    Directory of Open Access Journals (Sweden)

    Nachamai. M

    2013-01-01

    Full Text Available This paper is a sincere attempt to recognize english alphabets as part of hand gesture recognition, using the SIFT algorithm. The novelty of this approach is, it is a space, size, illumination and rotation invariant approach. The approach has evolved to work well with both the standard American Sign Language (ASL database and home-made database. The problem of alphabet recognition may seem to sound small but the intricacies involved in it cannot be solved using a single algorithm. Hand gesture recognition is a complicated task. A one stop solution is still not evolved for any recognition process. This paper has tried to approach this in a simple but efficient manner using the basic SIFT algorithm for recognition. The efficacy of the approach is proved well through the results obtained, invariably on both the datasets.

  10. Alphabet Recognition of American Sign Language : A Hand Gesture Recognition Approach Using Sift Algorithm

    Directory of Open Access Journals (Sweden)

    Nachamai. M

    2013-02-01

    Full Text Available This paper is a sincere attempt to recognize english alphabets as part of hand gesture recognition, usingthe SIFT algorithm. The novelty of this approach is, it is a space, size, illumination and rotation invariantapproach. The approach has evolved to work well with both the standard American Sign Language (ASLdatabase and home-made database. The problem of alphabet recognition may seem to sound small but theintricacies involved in it cannot be solved using a single algorithm. Hand gesture recognition is acomplicated task. A one stop solution is still not evolved for any recognition process. This paper has triedto approach this in a simple but efficient manner using the basic SIFT algorithm for recognition. Theefficacy of the approach is proved well through the results obtained, invariably on both the datasets.

  11. SIFT-based Ear Recognition by Fusion of Detected Keypoints from Color Similarity Slice Regions

    CERN Document Server

    Kisku, Dakshina Ranjan; Gupta, Phalguni; Sing, Jamuna Kanta

    2010-01-01

    Ear biometric is considered as one of the most reliable and invariant biometrics characteristics in line with iris and fingerprint characteristics. In many cases, ear biometrics can be compared with face biometrics regarding many physiological and texture characteristics. In this paper, a robust and efficient ear recognition system is presented, which uses Scale Invariant Feature Transform (SIFT) as feature descriptor for structural representation of ear images. In order to make it more robust to user authentication, only the regions having color probabilities in a certain ranges are considered for invariant SIFT feature extraction, where the K-L divergence is used for keeping color consistency. Ear skin color model is formed by Gaussian mixture model and clustering the ear color pattern using vector quantization. Finally, K-L divergence is applied to the GMM framework for recording the color similarity in the specified ranges by comparing color similarity between a pair of reference model and probe ear image...

  12. A Family of Non-isolated Bi-directional DC-DC Converters%一族非隔离双向直流变换器

    Institute of Scientific and Technical Information of China (English)

    吴红飞; 陆珏晶; 石巍; 张君君; 邢岩

    2012-01-01

    A family of non-isolated bi-directional DC converter (BDC) based on negative-coupled-inductor (NCI) was proposed. By utilizing the induced potential of the introduced NCI to block the body diode of MOSFET, the reverse-recovery problem associated with the body diode is eliminated. Furthermore, according to the analysis of the equivalent circuit of NCI and filter inductor, by replacing the two inductors with a positive-coupled-inductor (PCI), a family of non-isolated BDC based on PCI was proposed. The control of the proposed BDCs is the same as conventional unidirectional DC converter and has no extra soft start circuit required for the BDCs. The proposed BDCs have advantages of high efficiency, simple control and high reliability. The topology derivation process was presented and the operation principles of the proposed BDCs were analyzed in detail with experimental results given to verify the proposed topologies.%提出一族基于反向耦合电感的非隔离双向直流变换器foi.directionalDCconveaer,BDC),通过引入反向耦合电感,利用电感感应电势阻断不工作MOSFET的体二极管,消除了传统双向变换器中开关管寄生体二极管的反向恢复问题;通过反向耦合电感与滤波电感等效电路的分析,将反向耦合电感与滤波电感用一个同向耦合电感代替,提出一族基于PCI的非隔离双向直流变换器。所提出的变换器控制与传统单向变换器相同,不需要专门的软启动电路,兼顾了较高变换效率、控制简单和高可靠性。给出拓扑推演过程,详细分析拓扑工作原理,并通过实验验证理论分析的正确性。

  13. Bi-directional subduction of the South Tianshan Ocean during the Late Silurian: Magmatic records from both the southern Central Tianshan Block and northern Tarim Craton

    Science.gov (United States)

    Wang, Meng; Zhang, Jinjiang; Zhang, Bo; Liu, Kai; Ge, Maohui

    2016-10-01

    The subduction polarity of the South Tianshan Ocean (STO) is a matter of debate, primarily in that the Paleozoic structures of Tianshan orogenic belt have been strongly overprinted by the Cenozoic intra-continental deformation. Indentifying the arc-related magmatic rocks may provide a convincible clue for understanding the closure process of the STO. In this study, whole-rock geochemistry, zircon U-Pb dating and Hf isotope were presented on the andesite and monzonite from the Bayanbulak area of the southern Central Tianshan Block (CTB) and on the quartz diorite from the Ouxidaban area of the northern Tarim Craton. Geochemically, all the samples are Na-rich, enriched in light rare earth elements and large ion lithophile elements (Rb, Ba, U, K and Pb), and depleted in high strength field elements (Nb, Ta and Ti), like most arc-type igneous rocks. The Bayanbulak andesite samples display high MgO, Fe2O3T, TiO2 and Mg# values, and positive εHf(t) values, indicating magma source from the wedge mantle. But the existence of xenocrystic zircons implies that continental crust material were involved during magma ascend, suggesting a continental arc setting for the Bayanbulak andesite. The Bayanbulak monzonite and the Ouxidaban quartz diorite samples display relatively higher SiO2 contents, and lower MgO, Fe2O3T and TiO2 concentrations, indicating crustal sources. But the Mg# values of the Bayanbulak monzonite and the Ouxidaban quartz diorite are 48.76-51.85 and 50.31-53.73, and the εHf(t) values are -2.5 to 8.7 and -1.7 to 4.1, indicating that their magma sources were also mixed by mantle-derived components. LA-ICP-MS zircon U-Pb dating results reveal that the Bayanbulak andesite, the Bayanbulak monzonite and the Ouxidaban quartz diorite were formed at 423, 424 Ma, and 421 Ma, respectively. The age and geochemical data indicate that both the southern CTB and northern Tarim Craton were active continental margins during the Late Silurian, favoring a bi-directional subduction

  14. A subgroup of plant aquaporins facilitate the bi-directional diffusion of As(OH3 and Sb(OH3 across membranes

    Directory of Open Access Journals (Sweden)

    Wagner Annemarie

    2008-06-01

    Full Text Available Abstract Background Arsenic is a toxic and highly abundant metalloid that endangers human health through drinking water and the food chain. The most common forms of arsenic in the environment are arsenate (As(V and arsenite (As(III. As(V is a non-functional phosphate analog that enters the food chain via plant phosphate transporters. Inside cells, As(V becomes reduced to As(III for subsequent extrusion or compartmentation. Although much is known about As(III transport and handling in microbes and mammals, the transport systems for As(III have not yet been characterized in plants. Results Here we show that the Nodulin26-like Intrinsic Proteins (NIPs AtNIP5;1 and AtNIP6;1 from Arabidopsis thaliana, OsNIP2;1 and OsNIP3;2 from Oryza sativa, and LjNIP5;1 and LjNIP6;1 from Lotus japonicus are bi-directional As(III channels. Expression of these NIPs sensitized yeast cells to As(III and antimonite (Sb(III, and direct transport assays confirmed their ability to facilitate As(III transport across cell membranes. On medium containing As(V, expression of the same NIPs improved yeast growth, probably due to increased As(III efflux. Our data furthermore provide evidence that NIPs can discriminate between highly similar substrates and that they may have differential preferences in the direction of transport. A subgroup of As(III permeable channels that group together in a phylogenetic tree required N-terminal truncation for functional expression in yeast. Conclusion This is the first molecular identification of plant As(III transport systems and we propose that metalloid transport through NIPs is a conserved and ancient feature. Our observations are potentially of great importance for improved remediation and tolerance of plants, and may provide a key to the development of low arsenic crops for food production.

  15. 基于双向管理的社区白内障患者管理模式研究%Study on Bi-directional Management Mode of Patients with Cataract in Community

    Institute of Scientific and Technical Information of China (English)

    胡海双; 余雪如; 陈怡; 李超宏

    2016-01-01

    Objective To evaluate the influence of bi-directional management on emotional states, body symptoms and health status of patients with cataract in community and to provide rehabilitation guidelines.Methods From January 2014 and August 2015, 236 patients who had been diagnosed as senile cataract and had received phacoemulsification and intraocular lens implantation were included in this study and were divided into bi-directional management group and conventional intervention group randomly. After 4-month intervention, the performance evaluation was conducted through self-design questionnaire of following doctors' advice, Zung Self-rating Anxiety Scale, Self-rating Depression Scale and Chinese-version Low Vision Quality of Life questionnaire (CLVQOL).Results After 4-month intervention, scores of following doctors' advice in bi-directional management group were higher than that in conventional intervention group, scores of life quality in bi-directional management group improved more than that in conventional intervention group, anxiety and depression scores in bi-directional management group reduced more than that in conventional intervention group, and the differences were statistically significant (P<0.05).Conclusion Compared with conventional intervention group, patients in bi-directional management have better behavior of following doctors' advice, emotional states and life quality. Bi-directional management has positive influence on patients with cataract in community which is worth popularizing in community and clinical practice.%目的评价双向管理对社区白内障患者情绪状态、躯体症状及健康状态等的影响,为患者康复提供指导。方法选取本市2014年1月至2015年8月确诊为白内障且经白内障超声乳化联合晶状体植入术老年白内障患者236例,随机分为双向管理组与常规干预组,对其分别进行双向管理干预与常规干预,每月至少随访一次,干预4个月后,分别采用

  16. 图像匹配算法SIFT的改进%Improvement of image matching algorithm SIFT

    Institute of Scientific and Technical Information of China (English)

    姚文伟; 张智斌; 李国; 姜波

    2011-01-01

    Aiming at the proplem that the representability of each feature point needs 128-dimensional vector will reduce efficiency of SIFT algorithm, an improved SIFT algorithm was proposed which uses circle structure to substitute the original square structure and at the same time decrease the original dimension of SIFT algorithm characteristics description from 128 to 48. The experimental results showed that the method has faster speed of computation and higher precision of matching.%针对采用128维向量来表示每个特征点易导致SIFT算法效率降低的问题,提出了一种利用圆环城结构替代SIFT原来的方形结构、同时将原SIFT算法特征描述向量的维数由128维降为48维的改进SIFT算法.实验结果表明,改进算法比原SIFT算法具有更快的计算速度和更高的匹配精度.

  17. Breath testing and personal exposure--SIFT-MS detection of breath acetonitrile for exposure monitoring.

    Science.gov (United States)

    Storer, Malina; Curry, Kirsty; Squire, Marie; Kingham, Simon; Epton, Michael

    2015-05-26

    Breath testing has potential for the rapid assessment of the source and impact of exposure to air pollutants. During the development of a breath test for acetonitrile using selected ion flow tube mass spectrometry (SIFT-MS) raised acetonitrile concentrations in the breath of volunteers were observed that could not be explained by known sources of exposure. Workplace/laboratory exposure to acetonitrile was proposed since this was common to the volunteers with increased breath concentrations. SIFT-MS measurements of acetonitrile in breath and air were used to confirm that an academic chemistry laboratory was the source of exposure to acetonitrile, and quantify the changes that occurred to exhaled acetonitrile after exposure. High concentrations of acetonitrile were detected in the air of the chemistry laboratory. However, concentrations in the offices were not significantly different across the campus. There was a significant difference in the exhaled acetonitrile concentrations of people who worked in the chemistry laboratories (exposed) and those who did not (non-exposed). SIFT-MS testing of air and breath made it possible to determine that occupational exposure to acetonitrile in the chemistry laboratory was the cause of increased exhaled acetonitrile. Additionally, the sensitivity was adequate to measure the changes to exhaled amounts and found that breath concentrations increased quickly with short exposure and remained increased even after periods of non-exposure. There is potential to add acetonitrile to a suite of VOCs to investigate source and impact of poor air quality.

  18. Improved peroxyl radical scavenging TOSC assay to quantify antioxidant capacity using SIFT-MS.

    Science.gov (United States)

    Senthilmohan, Senti T; Davis, Brett M; Wilson, Paul F; McEwan, Murray J

    2009-01-01

    We report a new, fast, sensitive variation of the total oxyradical scavenging capacity (TOSC) assay for measuring the antioxidant capacity of pure compounds, plant extracts and biological fluids using selected ion flow tube mass spectrometry (SIFT-MS). The TOSC assay examines the partial inhibition of ethene formation in the presence of antioxidants that compete with alpha-keto-gamma-methiolbutyric acid (KMBA) for reactive oxygen species. The SIFT-MS-TOSC assay takes 15 s for each ethene analysis and the time interval between consecutive analyses is 20 s. We demonstrate the method by monitoring the antioxidant capacity of several standard radical scavengers of peroxyl radicals. For peroxyl radicals the measured SIFT-MS-TOSC concentrations necessary to produce 50% inhibition of radical reaction with KMBA are 6.1 +/- 0.3 microM for Trolox, 5.7 +/- 0.3 microM for ascorbic acid, 8.4 +/- 0.4 microM for uric acid and 38 +/- 2 microM for reduced glutathione.

  19. Compressed sense SIFT descriptor mixed with geometrical feature%融合几何特征的压缩感知SIFT描述子

    Institute of Scientific and Technical Information of China (English)

    赵爱罡; 王宏力; 杨小冈; 陆敬辉; 何星

    2015-01-01

    为了解决尺度不变特征变换(SIFT)描述子在存在较多相似结构的匹配中,易造成误匹配,并且维数较高、匹配耗时的问题,提出了一种融合相对几何位置的压缩感知描述子。首先,以特征点为中心,将周围关键点的相对几何位置( RGL )信息形成尺度和旋转不变的RGL描述子,其次,对SIFT描述子利用压缩感知(CS)理论进行降维,形成CS- SIFT描述子,最后将两者融合形成RGL- CS- SIFT描述子。实验结果表明:与SIFT和PCA-SIFT描述子相比,匹配速度有所提升,匹配准确率明显提高。%In order to solve the problems that SIFT (Scale Invariant Feature Transform, SIFT) descriptor may result in a lot mismatches when an image has many similar structures and its high dimensions will consume much time in image matching. This paper presents a compressive sensed SIFT descriptor which is mixed with relative geometry location. At first,this method centers on feature point,and transforms the information of relative geometry location related to around key points into a RGL (Relative Geometrical Location, RGL) descriptor, which is invariant to scale and rotation. Secondly, CS- SIFT (Compressive Sense SIFT, CS- SIFT)descriptor is formed by reducing dimensions of SIFT descriptor using the theory of compressive sense. At last, two descriptors form a RGL- CS- SIFT descriptor (descriptor mixed with RGL and CS- SIFT, RGL- CS- SIFT). The results indicate that the RGL- CS- SIFT increases the matching speed and improves the ratio of image matching significantly, compared with SIFT and PCA- SIFT (Principal Component Analysis SIFT, PCA- SIFT) descriptors.

  20. Structural interaction fingerprint (SIFt): a novel method for analyzing three-dimensional protein-ligand binding interactions.

    Science.gov (United States)

    Deng, Zhan; Chuaqui, Claudio; Singh, Juswinder

    2004-01-15

    Representing and understanding the three-dimensional (3D) structural information of protein-ligand complexes is a critical step in the rational drug discovery process. Traditional analysis methods are proving inadequate and inefficient in dealing with the massive amount of structural information being generated from X-ray crystallography, NMR, and in silico approaches such as structure-based docking experiments. Here, we present SIFt (structural interaction fingerprint), a novel method for representing and analyzing 3D protein-ligand binding interactions. Key to this approach is the generation of an interaction fingerprint that translates 3D structural binding information from a protein-ligand complex into a one-dimensional binary string. Each fingerprint represents the "structural interaction profile" of the complex that can be used to organize, analyze, and visualize the rich amount of information encoded in ligand-receptor complexes and also to assist database mining. We have applied SIFt to tackle three common tasks in structure-based drug design. The first involved the analysis and organization of a typical set of results generated from a docking study. Using SIFt, docking poses with similar binding modes were identified, clustered, and subsequently compared with conventional scoring function information. A second application of SIFt was to analyze approximately 90 known X-ray crystal structures of protein kinase-inhibitor complexes obtained from the Protein Databank. Using SIFt, we were able to organize the structures and reveal striking similarities and diversity between their small molecule binding interactions. Finally, we have shown how SIFt can be used as an effective molecular filter during the virtual chemical library screening process to select molecules with desirable binding mode(s) and/or desirable interaction patterns with the protein target. In summary, SIFt shows promise to fully leverage the wealth of information being generated in rational

  1. Research on control strategy for battery system of photovoltaic power system based on bi-directional DC/DC converter%基于双向变换器的光伏储能控制策略研究

    Institute of Scientific and Technical Information of China (English)

    李鑫; 解璞

    2016-01-01

    独立光伏系统中,储能环节起到平衡功率、稳定系统的关键作用,而合理的控制策略能将储能系统与光伏阵列有机地结合起来,双向 DC/DC变换器正是完成此目标的桥梁。本文在对已有的双向 DC/DC变换器进行优化设计的基础上,提出了一种兼顾电池电性能与系统稳定性的储能系统控制策略。在 Matlab仿真环境下搭建了带有双向 DC/DC变换器的独立光伏系统模型,并对储能系统的工作情况进行仿真,验证了变换器拓扑结构与储能控制策略的合理性。%The independent photovoltaic system needs energy storage in order to balance the power and improve its stability of power generation. A scientiifc control strategy can combine the PV cells with the battery system organically. The bi-directional DC/DC converter can be the bridge to achieve this target. This paper presents a control strategy which takes account of battery electrical performance and system stability based on optimization on the circuit topology of bi-directional DC/DC already underway. Moreover, the charge and discharge circuit based on bi-directional DC/DC converter and an integral independent PV power system are built with Matlab. The simulation results show the correctness of the charge and discharge circuit topology and control strategy.

  2. On the suitability of SIFT technique to deal with image modifications specific to confocal scanning laser microscopy.

    Science.gov (United States)

    Stanciu, Stefan G; Hristu, Radu; Boriga, Radu; Stanciu, George A

    2010-10-01

    Computer vision tasks such as recognition and classification of objects and structures or image registration and retrieval can provide significant information when applied to microscopy images. Recently developed techniques for the detection and description of local features make the extraction and description of local image features that are invariant to various changes possible. The invariance and robustness of feature detection and description techniques play a key role in the design and implementation of object recognition, image registration, or image mosaicing applications. The scale-invariant feature transform (SIFT) technique is a widely used method for the detection, description, and matching of image features. In this article we present the results of our experiments regarding the repeatability of SIFT features, and to the precision of the SIFT feature matching, under image modifications specific to confocal scanning laser microscopy (CSLM). We have analyzed the behavior of SIFT while changing the pinhole aperture, photomultiplier gain, laser beam power, and electronic zoom. Our experiments, conducted on CSLM images, show that the SIFT technique is able to match detected key points between images acquired at different values of the acquisition parameters with good precision and represents a consistent tool for computer vision applications in CSLM.

  3. Using an improved SIFT algorithm and fuzzy closed-loop control strategy for object recognition in cluttered scenes.

    Science.gov (United States)

    Nie, Haitao; Long, Kehui; Ma, Jun; Yue, Dan; Liu, Jinguo

    2015-01-01

    Partial occlusions, large pose variations, and extreme ambient illumination conditions generally cause the performance degradation of object recognition systems. Therefore, this paper presents a novel approach for fast and robust object recognition in cluttered scenes based on an improved scale invariant feature transform (SIFT) algorithm and a fuzzy closed-loop control method. First, a fast SIFT algorithm is proposed by classifying SIFT features into several clusters based on several attributes computed from the sub-orientation histogram (SOH), in the feature matching phase only features that share nearly the same corresponding attributes are compared. Second, a feature matching step is performed following a prioritized order based on the scale factor, which is calculated between the object image and the target object image, guaranteeing robust feature matching. Finally, a fuzzy closed-loop control strategy is applied to increase the accuracy of the object recognition and is essential for autonomous object manipulation process. Compared to the original SIFT algorithm for object recognition, the result of the proposed method shows that the number of SIFT features extracted from an object has a significant increase, and the computing speed of the object recognition processes increases by more than 40%. The experimental results confirmed that the proposed method performs effectively and accurately in cluttered scenes.

  4. 电动汽车与电网能量交互的双向变流器拓扑研究%Topology of Bi-directional Converter Used for Energy Interaction Between Electric Vehicle and Grid

    Institute of Scientific and Technical Information of China (English)

    鲍谚; 姜久春; 张宏韬; 牛利勇; 张维戈

    2012-01-01

    In view of the interaction technology between electric vehicle and gird, which has attracted widespread attention domestically and abroad, the bi-directional converter used as their energy interaction interface was investigated in this paper. Several typical topologies that suit for applying to electric vehicle bi-directional charger were introduced at first. Based on the comparison of characteristics and principles, a novel high power factor bi-directional single-stage full-bridge (BSS-FBC) topology was presented. This converter has the advantage of high efficiency, high power density, low harmonics, small volume, low cost, simple control, etc., The working principle and design of key parameters were introduced. Besides, the harmonic characteristic of this topology was analyzed through double-Fourier integral algorithm. On the basis of the topology and control strategy, a 3.3 kW prototype was developed. The excellent characteristics of this converter were verified by simulation and experiment.%针对国内外广泛关注的电动汽车与电网互动技术,对二者能量交互的接口——双向变流器进行了研究.首先分类介绍了几种典型的适用于电动汽车充放电机的电路拓扑,并对其主要特点和基本原理进行了比较和分析.在此基础上,提出了一种新颖的高功率因数双向单级全桥变换器(bi-directional single-phase single-stage full-bridge converter,BSS-FBC)拓扑,相比其他典型拓扑,该变换器具有效率高、功率密度高、谐波污染小、体积小、成本低、控制简单等特点.介绍了该拓扑的工作原理和设计要点,采用二重傅里叶积分方法对该拓扑进行了谐波特性分析.基于所提出的拓扑及控制方案,制作了一台功率为3.3 kW的样机,通过仿真和实验验证了该变换器的优良性能.

  5. 智能电表系统中的双向物理层辅助认证技术∗%Bi-Directional Physical Layer-Assist Authentication in Smart-Meter System

    Institute of Scientific and Technical Information of China (English)

    马婷; 任梦吟; 文红; 李腾飞

    2014-01-01

    Continuous bi-directional authentication is usually required between the smart meters,and however the existing upper-layer authentication technology based on encryption is not applicable to the resource-limited smart meters. Furthermore,the current physical layer assist authentication schemes could merely realize the one-way authentication from receiving terminal to source and not satisfy the authentication of bi-directional communication. This paper proposes a bi-directional physical layer-assist authentication scheme between smart meters. After initial message authentication based on PKI,physical-layer authentication is adopted in the follow-up authentication instead of relying on upper-layer authentication. Simulation results under IEEE 802.15.4g standard illustrate that this proposed scheme can achieve fast bi-directional authentication and is more applicable for smart meter system.%智能电表之间通常需要进行连续双向身份认证,而现有的基于加密的上层身份认证技术不适用于资源受限的智能电表系统。已有的物理层辅助身份认证机制仅能实现接收端到源的单向认证,不能满足智能电表之间双向通信的认证需求。文中提出一种适用于智能电表系统中的双向物理层辅助认证方案,该方案在完成基于PKI的初始消息认证后,在后续认证中使用物理层认证而无须依赖上层认证。基于IEEE802.11.4g标准的仿真结果表明,该方案能够实现快速双向身份认证,更适用于智能电表系统。

  6. Image stack alignment in full-field X-ray absorption spectroscopy using SIFT_PyOCL.

    Science.gov (United States)

    Paleo, Pierre; Pouyet, Emeline; Kieffer, Jérôme

    2014-03-01

    Full-field X-ray absorption spectroscopy experiments allow the acquisition of millions of spectra within minutes. However, the construction of the hyperspectral image requires an image alignment procedure with sub-pixel precision. While the image correlation algorithm has originally been used for image re-alignment using translations, the Scale Invariant Feature Transform (SIFT) algorithm (which is by design robust versus rotation, illumination change, translation and scaling) presents an additional advantage: the alignment can be limited to a region of interest of any arbitrary shape. In this context, a Python module, named SIFT_PyOCL, has been developed. It implements a parallel version of the SIFT algorithm in OpenCL, providing high-speed image registration and alignment both on processors and graphics cards. The performance of the algorithm allows online processing of large datasets.

  7. 改进的SIFT特征图像配准算法%Improved SIFT Feature Image Registration Algorithm

    Institute of Scientific and Technical Information of China (English)

    祁燕; 王琰; 王明宇

    2012-01-01

    在研究SIFT特征配准算法基础上,针对SIFT特征描述符的区域性特征,采用马氏距离对SIFT算法误匹配点进行剔除,以减少错误匹配,进而提高图像配准的正确率,并应用于纹理图像的配准.%It is aimed at districted feature of SIFT feature descriptor by studying the SIFT feature registration algorithm. In order to reduce the error registration, the Mahalanobis distance is used in SIFT algorithm. Part of the error registration points are eliminated by the improved algorithm. The precision of image registration is increased. And it is used in texture image registration.

  8. SIFT-Based Indoor Localization for Older Adults Using Wearable Camera.

    Science.gov (United States)

    Zhang, Boxue; Zhao, Qi; Feng, Wenquan; Sun, Mingui; Jia, Wenyan

    2015-04-01

    This paper presents an image-based indoor localization system for tracking older individuals' movement at home. In this system, images are acquired at a low frame rate by a miniature camera worn conveniently at the chest position. The correspondence between adjacent frames is first established by matching the SIFT (scale-invariant feature transform) based key points in a pair of images. The location changes of these points are then used to estimate the position of the wearer based on use of the pinhole camera model. A preliminary study conducted in an indoor environment indicates that the location of the wearer can be estimated with an adequate accuracy.

  9. Disposal of residue from sifting of combustible waste; Avsaettning av siktrest fraan foerbehandling av braennbart avfall

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik

    2012-11-01

    In waste to energy plants, unwanted species in the fuel may cause corrosion, deposits, agglomeration in the fuel bed, and emissions of pollutants. Countermeasures to such problems are often costly. For at least some of the waste, the fuel properties can be improved by introducing a pretreatment system in which the fine fraction is separated from the waste by sifting. This method has been studied in an earlier Waste Refinery project, WR-06. That study pointed at advantages in performance of the boiler plant and a rough economical analysis indicated substantial benefits. The drawback of the pretreatment was that the residue (the fine fraction) showed as high content of total organic carbon (TOC) as 37 %, by weight. Such a waste fraction is not allowed to be landfilled in Sweden. High TOC content is also a limiting factor for usage as a secondary construction material. To become an applicable pretreatment method, it is necessary to find an appropriate disposal method for the residue material. Present work investigates different possibilities to handle the sifting residue, assuming it has the same properties as in previous study. The residue from sifting needs further treatment, preferably with energy recovery. There are some alternatives, such as combustion, gasification, anaerobic or aerobic digestion. To reduce problems associated by combustion, the waste may be burnt in another more suitable furnace. An alternative is gasification, but that treatment method is not yet an established process for waste fuels. Another option is treatment by anaerobic or aerobic digestion. The high concentrations of metals, however, limit the use of the biologically treated waste to landfilling sites, where it may be utilized as a construction material. The high metal concentrations in the sifting residue imply that it must be kept separate from other biodegradable wastes which are used to produce fertilizers. Thus, this treatment alternative will likely require substantial new

  10. ALPRS - A New Approach for License Plate Recognition Using the SIFT Algorithm

    Directory of Open Access Journals (Sweden)

    F.A. Silva

    2013-03-01

    Full Text Available This paper presents a new approach for the automatic license plate recognition, which includes the SIFTalgorithm in step to locate the plate in the inputimage. In this new approach, besides the comparisonof thefeatures obtained with the SIFT algorithm, the correspondence between the spatial orientations and thepositioning associated with the keypoints is also observed. Afterwards, an algorithm is used for thecharacter recognition of the plates, very fast, which makes it possible its application in real time.Theresults obtained with the proposed approach presented very good success rates, so much for locating thecharacters in the input image, as for their recognition.

  11. The SIFT computer and its development. [Software Implemented Fault Tolerance for aircraft control

    Science.gov (United States)

    Goldberg, J.

    1981-01-01

    Software Implemented Fault Tolerance (SIFT) is an aircraft control computer designed to allow failure probability of less than 10 to the -10th/hour. The system is based on advanced fault-tolerance computing and validation methodology. Since confirmation of reliability by observation is essentially impossible, system reliability is estimated by a Markov model. A mathematical proof is used to justify the validity of the Markov model. System design is represented by a hierarchy of abstract models, and the design proof comprises mathematical proofs that each model is, in fact, an elaboration of the next more abstract model.

  12. Image Feature Matching Based on SIFT Algorithm%基于SIFT算法的图像特征匹配

    Institute of Scientific and Technical Information of China (English)

    周颖

    2015-01-01

    SIFT特征匹配算法的原理在于生成特征点的SIFT特征向量,通过对特征向量之间的匹配来实现图像之间的匹配。SIFT特征是一种尺度不变的局部图像特征,阐述生成SIFT特征向量的具体过程,包含尺度空间构建、关键点的检测和精确定位、关键点方向向量的确定和最终SIFT特征描述子的形成等步骤,以及根据形成的特征描述子进行图像的匹配。根据实验结果得出SIFT算法可以有效准确地实现图像之间的匹配。%The principle of SIFT feature matching algorithm is to generate SIFT feature vector of the characteristic points, through the matching of feature vector to realize the matching of the images. SIFT feature is a kind of local image characteristics which is invariant to image scale. Expounds the specific process of how SIFT feature vector is generated, including the building of the scale space, the detection of the key points and accurately positioning these points, determines the direction of the feature vector, and finally form the SIFT features vector and according to the vector to realize the image matching. According to the experimental results it is concluded that SIFT algorithm can effectively and accurately realize the matching of images.

  13. 一种改进的SIFT特征匹配算法%Improved SIFT Feature Matching Algorithm

    Institute of Scientific and Technical Information of China (English)

    于丽莉; 戴青

    2011-01-01

    Aiming at the problems of large calculating scale and high complexity in Scale Invariant Feature Transform(SIFT) feature matching algorithm, this paper presents an improved SIFT feature matching algorithm based on image Radon transform. It makes d beelines on different directions in image SIFT feature point zone. Image Radon transform integral values on d beelines are adopted as SIFT feature vector descriptors, it reduces the dimensions of SIFT feature vector to improve the efficiency of feature matching. Experimental result proves that the improved algorithm has higher matching accuracy and needs less matching time, it is quite suitable for high real-time demanded system such as virtual space roaming and target identification.%针对尺度不变特征变换(SIFT)特征匹配算法存在计算量大、复杂度高的问题,提出一种基于图像Radon变换的改进SIFT特征匹配算法.改进算法在图像的SIFT特征点采样区域内作d条不同方向的直线,以d条直线上的图像Radon变换作为SIFT特征向量描述符,降低SIFT特征向量的维数,从而提高特征匹配效率.实验结果表明,改进算法具有较高的匹配精度和较少的匹配时间,适用于虚拟场景漫游或目标识别等实时性要求较高的系统.

  14. A Multi-Level Grid Interactive Bi-directional AC/DC-DC/AC Converter and a Hybrid Battery/Ultra-capacitor Energy Storage System with Integrated Magnetics for Plug-in Hybrid Electric Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Onar, Omer C [ORNL

    2011-01-01

    This study presents a bi-directional multi-level power electronic interface for the grid interactions of plug-in hybrid electric vehicles (PHEVs) as well as a novel bi-directional power electronic converter for the combined operation of battery/ultracapacitor hybrid energy storage systems (ESS). The grid interface converter enables beneficial vehicle-to-grid (V2G) interactions in a high power quality and grid friendly manner; i.e, the grid interface converter ensures that all power delivered to/from grid has unity power factor and almost zero current harmonics. The power electronic converter that provides the combined operation of battery/ultra-capacitor system reduces the size and cost of the conventional ESS hybridization topologies while reducing the stress on the battery, prolonging the battery lifetime, and increasing the overall vehicle performance and efficiency. The combination of hybrid ESS is provided through an integrated magnetic structure that reduces the size and cost of the inductors of the ESS converters. Simulation and experimental results are included as prove of the concept presenting the different operation modes of the proposed converters.

  15. 一种软开关的交错并联Buck/Boost双向DC/DC变换器%A Type of Soft-Switching and Interleaving Bi-Directional DC/DC Converter

    Institute of Scientific and Technical Information of China (English)

    朱润卿; 刘军; 徐波

    2016-01-01

    针对传统硬开关双向直流变换器在高频工作时开关损耗较高的缺点,提出一种采用有源箝位软开关的多相交错并联Buck/Boost双向DC/DC变换器.这种变换器的开关管都能在零电压条件下开通,解决了开关管在开通时功率损耗较大的问题.借助SIMetrix软件工具,得出电路仿真结果,结果表明,变换器所有开关在Buck工作模式和Boost工作模式中均能实现软开关工作.%In view of the faults that traditional hard-switching bi-directional DC/DC converter working in high frequency caused much loss, a type of active clamped soft-switching of multiphase interleaving buck/boost bi-directional DC/DC converter is proposed, all switches of converter can be opened at zero voltage, it solves the problem of large loss of power switches.With the help of SIMetrix software tools, circuit simulation results are obtained.The simulation results show that the all switches of converter can achieve soft-switching in the buck mode and in the boost mode.

  16. 多层次SIFT特征在语义概念检测中的应用%Application of multiple-layer SIFT to semantic concept detection.

    Institute of Scientific and Technical Information of China (English)

    高赞; 赵志诚; 蔡安妮; 谢晓辉

    2011-01-01

    The Scale Invariant Feature Transform(SIFT) has been widely used in video concept detection. A lot of researches about SIFT have been done,such as PCA-SIFT, SURF and MESR.But there are few attentions about the influence of different down-sampling ratios to SIFT extraction. Based on the analysis of the influence of different down-sampling ratios to SIFT extraction, and a Multiple-Level SIFT(ML-SIFT) method for senmanfic concept detection is proposed. Experiments on Caltech256 and SceneC1ass13 show that MAPs of ML-SIFT outperform MAPs of SIFT on Caltech256 and SceneC1ass13 by 15.7% and 5.1% respectively. In addition,when training the modols using different ratios of positive and negative samples,the performances of ML-SIFT are stable. At the same time, the comparison of SIFT, SURF and ML-SIFT is given in the paper.From the experiments,the performances of SIFT and SURF are similar,but when comparing to ML-SIFT,their performances are worse than ML-SIFT. From above analysis,the ML-SIFT algorithm is effective.%SIFT局部特征因良好的性能在图像和视频的语义概念检测中得到广泛应用.已经有很多学者对SIFT深入研究,并提出了PCA-SIFT,SURF,MSER等,但是在SIFT算法中,阶与阶之间采样率的变化对SIFT特征的影响关注很少.考察了SIFT算法中,阶与阶之间采用不同降采样率对SIFT特征差异性的基础上,提出了一种多层次的SIFT(ML-SIFT)算法,Caltech256和SceneClassl3数据集上的实验表明,ML-SIFT相比于原始SIFT,其MAP的提高能够分别达到15.7%和5.1%.另外在Caltech256上,当采用不同比例的正负样本训练时,ML-SIFT算法具有较好的稳定性.同时,还将ML-SIFT算法,SIFT、SURF算法做了性能比较,SURF和SIFT算法的性能较接近,但是SIFT和SURF相对于ML-SIFT算法,则其性能较差.实验表明,ML-SIFT是有效的.

  17. A SIFT Algorithm for Bistatic SAR Imaging in a Spaceborne Constant-offset Configuration (in English

    Directory of Open Access Journals (Sweden)

    Chen Shi-chao

    2013-03-01

    Full Text Available This paper focuses on the problem of the space-variance of the range-cell migration term for bistatic Synthetic Aperture Radar (SAR and proposes a Scaled Inverse Fourier Transform (SIFT-based imaging algorithm for the constant-offset configuration of bistatic SAR data processing. Range-cell migration correction is realized when two times phase multiplies and a convolution operation are executed. Because the imaging algorithm is based on a precise spectrum that has been deduced from the Geometry-Based Formula (GBF algorithm, the proposed algorithm can handle the bistatic SAR data, which were obtained with a large baseline to ratio. The advantages and effectiveness of the proposed imaging method have been verified by simulated and comparable experiments. Moreover, unlike other scaling-imaging algorithms that are dependent on the frequency modulated characteristics of the signal, the SIFT imaging algorithm is also suitable for phase-coded signals, which are used in a wider range of applications.

  18. Tracking epithelial cell junctions in C. elegans embryogenesis with active contours guided by SIFT flow.

    Science.gov (United States)

    Kang, Sukryool; Lee, Chen-Yu; Gonçalves, Monira; Chisholm, Andrew D; Cosman, Pamela C

    2015-04-01

    Quantitative analysis of cell shape in live samples is an important goal in developmental biology. Automated or semi-automated segmentation and tracking of cell nuclei has been successfully implemented in several biological systems. Segmentation and tracking of cell surfaces has been more challenging. Here, we present a new approach to tracking cell junctions in the developing epidermis of C. elegans embryos. Epithelial junctions as visualized with DLG-1::GFP form lines at the subapical circumference of differentiated epidermal cells and delineate changes in epidermal cell shape and position. We develop and compare two approaches for junction segmentation. For the first method (projection approach), 3-D cell boundaries are projected into 2D for segmentation using active contours with a nonintersecting force, and subsequently tracked using scale-invariant feature transform (SIFT) flow. The resulting 2-D tracked boundaries are then back-projected into 3-D space. The second method (volumetric approach) uses a 3-D extended version of active contours guided by SIFT flow in 3-D space. In both methods, cell junctions are manually located at the first time point and tracked in a fully automated way for the remainder of the video. Using these methods, we have generated the first quantitative description of ventral epidermal cell movements and shape changes during epidermal enclosure.

  19. Localisation of the brain in fetal MRI using bundled SIFT features.

    Science.gov (United States)

    Keraudren, Kevin; Kyriakopoulou, Vanessa; Rutherford, Mary; Hajnal, Joseph V; Rueckert, Daniel

    2013-01-01

    Fetal MRI is a rapidly emerging diagnostic imaging tool. Its main focus is currently on brain imaging, but there is a huge potential for whole body studies. We propose a method for accurate and robust localisation of the fetal brain in MRI when the image data is acquired as a stack of 2D slices misaligned due to fetal motion. We first detect possible brain locations in 2D images with a Bag-of-Words model using SIFT features aggregated within Maximally Stable Extremal Regions (called bundled SIFT), followed by a robust fitting of an axis-aligned 3D box to the selected regions. We rely on prior knowledge of the fetal brain development to define size and shape constraints. In a cross-validation experiment, we obtained a median error distance of 5.7mm from the ground truth and no missed detection on a database of 59 fetuses. This 2D approach thus allows a robust detection even in the presence of substantial fetal motion.

  20. 基于模糊控制的电动车双向DC-DC变换器研究%Research on the Bi-Directional DC-DC Converter of the Electric Vehicle Based on the Fuzzy Control

    Institute of Scientific and Technical Information of China (English)

    崔雪; 郑翔; 穆佩红; 高雅洁

    2014-01-01

    为了延长车辆续航里程,提高蓄电池的使用寿命,使用超级电容作为辅助的能量源,控制超级电容的双向DC-DC变换器对直流母线进行能量的回馈和补充,提高了电动车电源系统效率。根据蓄电池和超级电容的剩余电量及负载瞬态功率需求,提出了一种模糊控制器改善双能量电动车DC-DC变换器性能的方法。模糊控制器根据车辆运行的不同工况,自动地决策出一个合理的输出电流,进而控制双向半桥Buck/Boost式变换器的电流环。实验结果说明了控制系统具有良好的动态性、可行性、有效性。%In order to prolong the driving range and the life cycle of the storage battery, ultracapcitor was used in this study as an auxiliary power source, the bi-directional DC-DC converter of the ultracapacitor was controlled to supplement the energy of the DC bus, and thus the efficiency of the electric vehicle power system was enhanced. Based on the dump energy of the storage battery and ultracapacitor and the need for load transient power, a method was proposed in this paper, in which a fuzzy controller was adopted to improve the performance of the bi-directional DC-DC converter of the electric vehicle. The fuzzy controller could automatically decide on proper output current according to different working conditions of the vehicle, and thereby control the current loop of the bi-directional half-bridge Buck/Boost converter. Simulation results proved that the control system was very dynamic, feasible and effective.

  1. Quantification of trace levels of the potential cancer biomarkers formaldehyde, acetaldehyde and propanol in breath by SIFT-MS.

    Science.gov (United States)

    Spaněl, Patrik; Smith, David

    2008-12-01

    The sensitivity of selected ion flow tube mass spectrometry, SIFT-MS, has been increased such that it is now possible to detect metabolites present at a part-per-billion, ppb, level in single breath exhalations. However, to utilize this improved sensitivity, the overlaps (coincidences) of those ions resulting from interfering reactions of impurity precursor ions with some breath metabolites present at higher concentrations with the analytical product ions characteristic of particular metabolites must be accounted for. In this paper, the full reaction schemes are presented for SIFT-MS analyses of three volatile potential cancer biomarkers in exhaled breath, namely formaldehyde, HCHO, acetaldehyde, CH(3)CHO and 2-propanol, CH(3)CH(OH)CH(3), which identify both the characteristic SIFT-MS product ions for these compounds and the interfering ions at the same mass-to-charge, m/z, values. An absolute quantification equation accounting for these interferences is formulated and appropriate entries into the SIFT-MS kinetics library are indicated. It is shown that when using H(3)O(+) to quantify formaldehyde and acetaldehyde the reactions of impurity O(2)(+) ions with methanol and ethanol (always present in breath) must be accounted for and that the quantification of acetaldehyde must avoid the interference of the CO(2) present in exhaled breath. Finally, it is indicated that the analysis of 2-propanol can be achieved using both H(3)O(+) and NO(+) precursor ions.

  2. Unsupervised semantic indoor scene classification for robot vision based on context of features using Gist and HSV-SIFT

    Science.gov (United States)

    Madokoro, H.; Yamanashi, A.; Sato, K.

    2013-08-01

    This paper presents an unsupervised scene classification method for actualizing semantic recognition of indoor scenes. Background and foreground features are respectively extracted using Gist and color scale-invariant feature transform (SIFT) as feature representations based on context. We used hue, saturation, and value SIFT (HSV-SIFT) because of its simple algorithm with low calculation costs. Our method creates bags of features for voting visual words created from both feature descriptors to a two-dimensional histogram. Moreover, our method generates labels as candidates of categories for time-series images while maintaining stability and plasticity together. Automatic labeling of category maps can be realized using labels created using adaptive resonance theory (ART) as teaching signals for counter propagation networks (CPNs). We evaluated our method for semantic scene classification using KTH's image database for robot localization (KTH-IDOL), which is popularly used for robot localization and navigation. The mean classification accuracies of Gist, gray SIFT, one class support vector machines (OC-SVM), position-invariant robust features (PIRF), and our method are, respectively, 39.7, 58.0, 56.0, 63.6, and 79.4%. The result of our method is 15.8% higher than that of PIRF. Moreover, we applied our method for fine classification using our original mobile robot. We obtained mean classification accuracy of 83.2% for six zones.

  3. Target Recognition Algorithm Based on PCA-SIFT%基于PCA-SIFT特征的目标识别算法

    Institute of Scientific and Technical Information of China (English)

    王鹤; 谢刚

    2013-01-01

    In this paper,a target identification and matching algorithm based on PCA-SIFT is proposed to deal with the problem that a long time is taken caused by excessive number of characteristics in the matching with SIFT algorithm.Firstly,the robust and salient feature points and vectors of the image frames according to the local invariant features is extracted.Then,PCA analytic method is introduced into image matching to reduce the dimensions of SIFT feature vector.Finally,use the reduced feature points to image matching and analytic methods.Experimental results show that the algorithm proposed in this.paper not only has maintain the robustness and stability,but also improves the matching efficiency and enhancing the real-time performance,comparing with the original SIFT algorithm.%针对尺度不变特征变换(SIFT)算法在匹配时特征向量过多,从而导致耗时过长的问题,提出PCA-SIF]算法,对目标进行匹配与识别.首先,利用SIFT算法提取出原图像中稳健的特征点以及特征向量;其次,利用PCA算法对SIFT特征向量的维数进行约减;最后利用降维后的图像与原始图像进行匹配.实验证明,与原始SIFT算法相比,该算法不仅保持了SIFT算法的鲁棒性和稳定性,同时提高了匹配效率,增强了实时性.

  4. 基于网络编码的双向多中继系统中断概率分析%Outage Probability Analysis of Bi-directional Multi-Relay System Based on Network Coding

    Institute of Scientific and Technical Information of China (English)

    梁文文; 徐友云; 田华; 许魁

    2012-01-01

    Network Coding has been investigated extensively in bi-directional multi-relay system and can improve the throughput of bi-directional multi-relay system effectually. Firstly two outage probability expressions of bi-directional multi-relay system on independent orthogonal channel and multiple access channel with decode-and-forward based on network coding are given in this paper and theory analysis is proved correct by Monte Carlo simulation. Secondly we analyze the system average outage performance at different situation of different power allocation coefficient, SNR and the number of relay, indicating the inherent relationship between power allocation coefficient and total system power as well as the number of relay. Simulation results indicate that optimal system outage performances of bi-directional multi-relay system on the two channels are attained when power allocation coefficient is chosen in[0.5,0.6] , and we can see that outage performance of the system on multiple access channel is better than the independent orthogonal channel.%网络编码在双向多中继系统中已经得到了广泛地研究,并有效地提高了双向多中继系统的吞吐量.首先本文导出了在译码转发方式时,独立正交信道和多接入信道下基于网络编码的双向多中继系统平均中断概率表达式.Monte Carlo仿真和理论分析非常吻合,验证了理论分析的正确性.之后分析了系统平均中断性能在不同信噪比和不同中继节点个数等多种情形下与功率分配因子的关系,揭示了功率分配因子与系统总功率和中继节点数量之间的内在关系.仿真结果表明,双向多中继系统采用网络编码进行传输时,在独立正交信道下和多接入信道下的功率分配因子取值在区间[0.5,0.6]内能够获得最优的系统中断概率性能,并且多接入信道下的系统中断性能要好于独立正交信道.

  5. Video Retrieval using Histogram and Sift Combined with Graph-based Image Segmentation

    Directory of Open Access Journals (Sweden)

    Bui Ngo Da Thao

    2012-01-01

    Full Text Available Problem statement: Content-Based Video Retrieval (CBVR is still an open hard problem because of the semantic gap between low-level features and high-level features, largeness of database, keyframe’s content, choosing feature.In this study we introduce a new approach for this problem based on Scale-Invariant Feature Transform (SIFT feature, a new metric and an object retrieval method. Conclusion/Recommendations: Our algorithm is built on a Content-Based Image Retrieval (CBIR method in which the keyframe database includes keyframes detected from video database by using our shot detection method. Experiments show that the approach of our algorithmhas fairly high accuracy.

  6. A Comparison between Using SIFT and SURF for Characteristic Region Based Image Steganography

    Directory of Open Access Journals (Sweden)

    Nagham Hamid

    2012-05-01

    Full Text Available Steganography is the science of invisible communication that employs different useful applications. In most of the current steganography techniques, information hiding modifies almost all the cover image, which may negatively affect the visual quality of the image and increase the possibility of losing data after the possible attacks. To solve such a problem, this paper presents a new region based steganography technique, which hides data in the robust regions of the image. Two promising approaches have been used to detect the robust regions in the image: Scale Invariant Feature Transform (SIFT and Speeded Up Robust Features (SURF. The robustness of the two algorithms has been tested against different types of attacks. Results showed that SURF based algorithm is better when detecting the robust regions correctly; its accuracy is higher in retrieving the embedded data and that the visual quality of the embedded image is high for both algorithms.

  7. [Research on non-rigid medical image registration algorithm based on SIFT feature extraction].

    Science.gov (United States)

    Wang, Anna; Lu, Dan; Wang, Zhe; Fang, Zhizhen

    2010-08-01

    In allusion to non-rigid registration of medical images, the paper gives a practical feature points matching algorithm--the image registration algorithm based on the scale-invariant features transform (Scale Invariant Feature Transform, SIFT). The algorithm makes use of the image features of translation, rotation and affine transformation invariance in scale space to extract the image feature points. Bidirectional matching algorithm is chosen to establish the matching relations between the images, so the accuracy of image registrations is improved. On this basis, affine transform is chosen to complement the non-rigid registration, and normalized mutual information measure and PSO optimization algorithm are also chosen to optimize the registration process. The experimental results show that the method can achieve better registration results than the method based on mutual information.

  8. Courier Receipts Retrieval System Design Combining the Inverse Zernike Moments and the SIFT Features

    Directory of Open Access Journals (Sweden)

    Wenyin Ni

    2012-11-01

    Full Text Available In response to the demand of the logistics industry’s application, a retrieval algorithm for logistics bill is proposed which combines the local feature with the global feature of images, which solved the problem of rotation positioning and applied to a set of practical courier receipts retrieval system. By using the scale invariance principle of the local features combined with Zernike invariant moments of the global features, we can quickly calculate the image rotating angle and make the exact match. Experimental results show that this method not only keeps the well precision and recall ratio ability of SIFT features, but also reduces the counting times which are required by fine matching.

  9. 3D point cloud registration based on the assistant camera and Harris-SIFT

    Science.gov (United States)

    Zhang, Yue; Yu, HongYang

    2016-07-01

    3D(Three-Dimensional) point cloud registration technology is the hot topic in the field of 3D reconstruction, but most of the registration method is not real-time and ineffective. This paper proposes a point cloud registration method of 3D reconstruction based on Harris-SIFT and assistant camera. The assistant camera is used to pinpoint mobile 3D reconstruction device, The feature points of images are detected by using Harris operator, the main orientation for each feature point is calculated, and lastly, the feature point descriptors are generated after rotating the coordinates of the descriptors relative to the feature points' main orientations. Experimental results of demonstrate the effectiveness of the proposed method.

  10. FINGER KNUCKLE PRINT RECOGNITION WITH SIFT AND K-MEANS ALGORITHM

    Directory of Open Access Journals (Sweden)

    A. Muthukumar

    2013-02-01

    Full Text Available In general, the identification and verification are done by passwords, pin number, etc., which is easily cracked by others. Biometrics is a powerful and unique tool based on the anatomical and behavioral characteristics of the human beings in order to prove their authentication. This paper proposes a novel recognition methodology of biometrics named as Finger Knuckle print (FKP. Hence this paper has focused on the extraction of features of Finger knuckle print using Scale Invariant Feature Transform (SIFT, and the key points are derived from FKP are clustered using K-Means Algorithm. The centroid of K-Means is stored in the database which is compared with the query FKP K-Means centroid value to prove the recognition and authentication. The comparison is based on the XOR operation. Hence this paper provides a novel recognition method to provide authentication. Results are performed on the PolyU FKP database to check the proposed FKP recognition method.

  11. SIFT and shape information incorporated into fluid model for non-rigid registration of ultrasound images.

    Science.gov (United States)

    Lu, Xuesong; Zhang, Su; Yang, Wei; Chen, Yazhu

    2010-11-01

    Non-rigid registration of ultrasound images takes an important role in image-guided radiotherapy and surgery. Intensity-based method is popular in non-rigid registration, but it is sensitive to intensity variations and has problems with matching small structure features for the existence of speckles in ultrasound images. In this paper, we develop a new algorithm integrating the intensity and feature of ultrasound images. Both global shape information and local keypoint information extracted by scale invariant feature transform (SIFT) are incorporated into intensity similarity measure as the body force of viscous fluid model in a Bayesian framework. Experiments were performed on synthetic and clinical ultrasound images of breast and kidney. It is shown that shape and keypoint information significantly improves fluid model for non-rigid registration, especially for alignment of small structure features in accuracy.

  12. EEGLAB, SIFT, NFT, BCILAB, and ERICA: new tools for advanced EEG processing.

    Science.gov (United States)

    Delorme, Arnaud; Mullen, Tim; Kothe, Christian; Akalin Acar, Zeynep; Bigdely-Shamlo, Nima; Vankov, Andrey; Makeig, Scott

    2011-01-01

    We describe a set of complementary EEG data collection and processing tools recently developed at the Swartz Center for Computational Neuroscience (SCCN) that connect to and extend the EEGLAB software environment, a freely available and readily extensible processing environment running under Matlab. The new tools include (1) a new and flexible EEGLAB STUDY design facility for framing and performing statistical analyses on data from multiple subjects; (2) a neuroelectromagnetic forward head modeling toolbox (NFT) for building realistic electrical head models from available data; (3) a source information flow toolbox (SIFT) for modeling ongoing or event-related effective connectivity between cortical areas; (4) a BCILAB toolbox for building online brain-computer interface (BCI) models from available data, and (5) an experimental real-time interactive control and analysis (ERICA) environment for real-time production and coordination of interactive, multimodal experiments.

  13. Unsupervised unstained cell detection by SIFT keypoint clustering and self-labeling algorithm.

    Science.gov (United States)

    Muallal, Firas; Schöll, Simon; Sommerfeldt, Björn; Maier, Andreas; Steidl, Stefan; Buchholz, Rainer; Hornegger, Joachim

    2014-01-01

    We propose a novel unstained cell detection algorithm based on unsupervised learning. The algorithm utilizes the scale invariant feature transform (SIFT), a self-labeling algorithm, and two clustering steps in order to achieve high performance in terms of time and detection accuracy. Unstained cell imaging is dominated by phase contrast and bright field microscopy. Therefore, the algorithm was assessed on images acquired using these two modalities. Five cell lines having in total 37 images and 7250 cells were considered for the evaluation: CHO, L929, Sf21, HeLa, and Bovine cells. The obtained F-measures were between 85.1 and 89.5. Compared to the state-of-the-art, the algorithm achieves very close F-measure to the supervised approaches in much less time.

  14. EEGLAB, SIFT, NFT, BCILAB, and ERICA: New Tools for Advanced EEG Processing

    Directory of Open Access Journals (Sweden)

    Arnaud Delorme

    2011-01-01

    Full Text Available We describe a set of complementary EEG data collection and processing tools recently developed at the Swartz Center for Computational Neuroscience (SCCN that connect to and extend the EEGLAB software environment, a freely available and readily extensible processing environment running under Matlab. The new tools include (1 a new and flexible EEGLAB STUDY design facility for framing and performing statistical analyses on data from multiple subjects; (2 a neuroelectromagnetic forward head modeling toolbox (NFT for building realistic electrical head models from available data; (3 a source information flow toolbox (SIFT for modeling ongoing or event-related effective connectivity between cortical areas; (4 a BCILAB toolbox for building online brain-computer interface (BCI models from available data, and (5 an experimental real-time interactive control and analysis (ERICA environment for real-time production and coordination of interactive, multimodal experiments.

  15. Real-time multi-modal rigid registration based on a novel symmetric-SIFT descriptor

    Institute of Scientific and Technical Information of China (English)

    Jian Chen; Jie Tian

    2009-01-01

    The purpose of image registration is to spatially align two or more single-modality images taken at different times,or several images acquired by multiple imaging modalities.Intensity-based registration usually requires optimization of the similarity metric between the images.However,global optimization techniques are too time-consuming,and local optimization techniques frequently fail to search the global transformation space because of the large initial misalignment of the two images.Moreover,for large non-overlapping area registration,the similarity metric cannot reach its optimum value when the two images are properly registered.In order to solve these problems,we propose a novel Symmetric Scale Invariant Feature Transform (symmetric-SIFT) descriptor and develop a fast multi-modal image registration technique.The proposed technique automatically generates a lot of highly distinctive symmetric-SIFT descriptors for two images,and the registration is performed by matching the corresponding descriptors over two images.These descriptors are invariant to image scale and rotation,and are partially invariant to affine transformation.Moreover,these descriptors are symmetric to contrast,which makes it suitable for multi-modal image registration.The proposed technique abandons the optimization and similarity metric strategy.It works with near real-time performance,and can deal with the large non-overlapping and large initial misalignment situations.Test cases involving scale change,large non-overlapping,and large initial misalignment on computed tomography (CT) and magnetic resonance (MR) datasets show that it needs much less runtime and achieves better accuracy when compared to other algorithms.(C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences.Published by Elsevier Limited and Science in China Press.All rights reserved.

  16. Object Recognition System in Remote Controlled Weapon Station using SIFT and SURF Methods

    Directory of Open Access Journals (Sweden)

    Midriem Mirdanies

    2013-12-01

    Full Text Available Object recognition system using computer vision that is implemented on Remote Controlled Weapon Station (RCWS is discussed. This system will make it easier to identify and shoot targeted object automatically. Algorithm was created to recognize real time multiple objects using two methods i.e. Scale Invariant Feature Transform (SIFT and Speeded Up Robust Features (SURF combined with K-Nearest Neighbors (KNN and Random Sample Consensus (RANSAC for verification. The algorithm is designed to improve object detection to be more robust and to minimize the processing time required. Objects are registered on the system consisting of the armored personnel carrier, tanks, bus, sedan, big foot, and police jeep. In addition, object selection can use mouse to shoot another object that has not been registered on the system. Kinect™ is used to capture RGB images and to find the coordinates x, y, and z of the object. The programming language used is C with visual studio IDE 2010 and opencv libraries. Object recognition program is divided into three parts: 1 reading image from kinect™ and simulation results, 2 object recognition process, and 3 transfer of the object data to the ballistic computer. Communication between programs is performed using shared memory. The detected object data is sent to the ballistic computer via Local Area Network (LAN using winsock for ballistic calculation, and then the motor control system moves the direction of the weapon model to the desired object. The experimental results show that the SIFT method is more suitable because more accurate and faster than SURF with the average processing time to detect one object is 430.2 ms, two object is 618.4 ms, three objects is 682.4 ms, and four objects is 756.2 ms. Object recognition program is able to recognize multi-objects and the data of the identified object can be processed by the ballistic computer in realtime.

  17. 一种基于SIFT算法的图像镜像变换识别方法%Method based on SIFT for recognition of flip images

    Institute of Scientific and Technical Information of China (English)

    及莹; 陆月明

    2013-01-01

    SIFT(scale invariant feature transform)算法提取的图像特征对图像自身的镜像变换匹配精度不够.针对此问题,对SIFT算法进行了改进,提出FI-SIFT(flip invariant SIFT)算法:利用纵坐标方向的梯度初步判断图像是否为镜像变换,若是则把特征向量映射为极坐标,对极坐标进行重组后,再逆变换到直角坐标系,更新特征向量;然后基于欧式距离匹配两幅图像中的关键点.实验结果表明,采用FI-SIFI算法提取的图像特征进行镜像变换匹配,匹配精度有了很大提高,由改进之前的0.6上升到0.9.%The image feature extracted by SIFT algorithm does not match the mirror transform of image itself very well. Aiming at this problem,this paper modified the SIFT algorithm, and proposed the FI-SIFT algorithm. The FI-SIFT algorithm firstly used the gradient of Y-axis to determine whether it was a mirror transform, if it was, mapped the descriptor to polar coordinate. After the reassembling the polar coordinates, the new descriptor could be obtained in the Cartesian coordinates by reverse transform. Then matched the critical points by Euler distance. The experimental results show that the image features obtained by the FI-SIFT algorithm match the mirror transformation of the image much better. The average matching accuracy rises from 0.6 to 0.9.

  18. 基于SiftGPU特征匹配方法的实时视觉里程计系统%Real-time visual odometry system based on SiftGPU

    Institute of Scientific and Technical Information of China (English)

    张云; 尹露; 王雨婷; 罗斌

    2015-01-01

    The visual odometry method is adopted based on Scale Invariant Feature Transform(SIFT) to get stereo corresponding points for motion estimation between every two binocular frames. Then the rotation and translation matrix is employed to invert the moving path of the robot. SiftGPU is applied to accelerate computing so that real-time visual odometry system can be achieved. RANSAC algorithm is adopted to eliminate mismatching interference. Experimental results show that SIFT algorithm with strong scale and affine transform invariance can get more accurate path inversion results; and GPU graphics acceleration will achieve real-time visual positioning.%采用尺度不变特征变换(SIFT)特征匹配方法对双目相机图像进行立体匹配,同时匹配相邻两时刻的三维点,求解运动方程进行运动估计,得到机器人 2 个时刻坐标变换的旋转和平移参数;使用每 2个时刻的旋转和平移结果进行机器人的路径反演,采用 GPU加速 SIFT特征提取与匹配,实现实时的视觉里程计系统,并采用 RANSAC 算法用于运动估计剔除误匹配点干扰.实验结果表明,具有仿射变换较强不变性的 SIFT特征匹配算法能够得到较为精确的路径反演结果,采用 GPU加速 SIFT特征提取与匹配能达到实时的视觉定位效果.

  19. Performability evaluation of the SIFT computer. [Software-Implemented Fault Tolerance computer onboard commercial aircraft during transoceanic flight

    Science.gov (United States)

    Meyer, J. F.; Furchtgott, D. G.; Wu, L. T.

    1980-01-01

    The paper deals with the models, techniques, and evaluation methods that were successfully used to test the performance of the SIFT degradable computing system. The performance of the computer plus its air transport mission environment is modeled as a random variable, taking values in a set of 'accomplishment level'. The levels are defined in terms of four attributes of total system (computer plus environment) behavior, namely safety, no change in mission profile, no operational penalties, and no economic penalties. The base model of the total system is a stochastic process, whose states describe the internal structure of SIFT and the relevant conditions of its computational environment. Base model state trajectories are related to accomplishment levels via a special function, and solution methods are then used to determine the performability of the total system for various parameters of the computer and environment.

  20. Real time monitoring of population dynamics in concurrent bacterial growth using SIFT-MS quantification of volatile metabolites.

    Science.gov (United States)

    Sovová, Kristýna; Čepl, Jaroslav; Markoš, Anton; Španěl, Patrik

    2013-09-07

    Population dynamics of three different bacterial species, Serratia rubidaea (R), Serratia marcescens (F) and Escherichia coli (Ec), growing in single or mixed populations in liquid media, was monitored by real time headspace quantification of volatile compounds using selected ion flow tube mass spectrometry, SIFT-MS. The three bacterial species interact with each other in a competitive fashion in a way similar to the game "rock-paper-scissors" (R-Ec-F). The concentrations of volatile metabolites (ammonia, ethanol, acetaldehyde, propanol, acetoin, acetone and acetic acid) were measured in the headspace of the individual species and of their mixtures continuously for 24 hour periods. The results demonstrate that dynamics in bacterial cultures can be monitored using SIFT-MS in real time.

  1. Toxicity-reducing and efficacy-maintaining function of fungal fermentative products in Tripterygium wilfordii by Ganoderma lucidum bi-direction solid fermentation%灵芝双向发酵雷公藤的解毒持效作用

    Institute of Scientific and Technical Information of China (English)

    谢小梅; 贺婧; 罗闳丹; 苏明声; 张普照; 庄毅

    2009-01-01

    目的 研究灵芝双向发酵对雷公藤的解毒持效作用.方法 运用双向发酵工程的原理和方法 获得灵雷菌质(G30),用常规急性毒性试验,免疫学试验、自身免疫疾病动物模型试验等进行G30的毒性和药效学研究.结果 G30的LD_(50)较雷公藤生药组显著提高,并且能抑制小鼠T、B淋巴细胞的增殖和血清溶血素的分泌;G30降低阿霉素诱导的肾炎大鼠的24 h尿蛋白量,同时改善肾炎大鼠的多项生化指标,且对各脏器的毒性要小于雷公藤生药;G30缓解佐剂性类风湿关节炎大鼠的足肿胀度,并改善大鼠的生存状况.结论 灵芝与雷公藤构成发酵组合所产灵雷菌质G30毒性降低并仍然保持免疫抑制作用,对佐剂性类风湿关节炎及阿霉素诱导的大鼠肾炎均有一定的治疗作用.显示双向发酵对雷公藤解毒持效是一条可行的途径.%Objective To survey the toxicity-reducing and efficacy-maintaining function of fungal fermentative products in Tripterygium wilfordii by Ganoderma lucidum bi-direction solid fermentation.Methods Bi-direction solid fermentation engineering was applied and Linglei fungal substance(G30)was obtained.Its toxicity and pharmacodynamics were detected with regular acute toxicity test,immunological test,and tests on autoimmune disease animal pattern.Results LD_(50) of G30 was higher than that of crude drug.G30 had the inhibiting effect on proliferation of both T and B lymphoeytes and could decrease the production of hemolysin in mice.G30 could decrease 24 h urine protein of nephritis model of rats caused by Adriamycin.and it had less toxicity on organs than T. wilfordii.G30 could alleviate foot swelling of rheumatoid arthritis model.Conclusion Linglei fungal substance is obtained from the fermentative composition of G.lucidum fungal and T.wilfordii.It shows lOW toxicity and effects of immunosuppression and also has some therapeutic effects on the model of autoimmune diseases

  2. 一种改进的SIFT图像特征匹配算法%Improved SIFT image feature matching algorithm

    Institute of Scientific and Technical Information of China (English)

    张永; 武玉建

    2014-01-01

    Aiming at the problem that high dimension of SIFT feature description operator causes large calculating scale and high complexity in SIFT image feature matching algorithm, this paper proposes an improved SIFT image feature matching algorithm based on kernel projection. Instead of using smoothed weighted histograms to calculate gradient modulus and gradient orientations, this paper proposes an improved scheme based on kernel projection. It reduces the dimension of SIFT feature description and improves the efficiency of feature matching. Experimental result proves that the improved algo-rithm has higher matching accuracy and has less matching time, and it has higher instantaneity.%针对传统SIFT图像特征匹配算法因其特征描述算子维度过高而造成的计算量大、实时性差的问题,提出一种基于内核投影的改进SIFT图像特征匹配算法。传统SIFT特征匹配算法采用平滑加权直方图计算特征点的梯度模值和梯度方向。采用内核投影算法对其进行改进,使生成的特征描述算子的维度降低,从而能够提高特征匹配效率。实验结果表明,改进后的SIFT算法具有较高的匹配精度,同时匹配时间有所减少,使实时性得到提高。

  3. 基于SIFT特征的视频稳像算法%Video Stabilization Algorithm Based on SIFT Feature

    Institute of Scientific and Technical Information of China (English)

    陈滨; 杨利斌; 赵建军

    2016-01-01

    为将载体上截取的视频进行稳像,介绍了尺度不变特征变换(scale invariant feature transform,SIFT)算法及基于SIFT特征的视频稳像算法.基于电子稳像算法框架采用六参数仿射模型表征图像运动,利用图像的SIFT特征估计图像间的模型参数,通过补偿来消除图像间的运动,完成了视频稳像任务.最后,利用峰值信噪比(peak signal to noise ratio,PSNR)指标评价稳像效果.实验结果表明:该算法能很好地消除图像间的运动,有效提高图像间的PSNR值,完成视频序列的稳像任务.%In order to stabilize the video obtained from cameras on kinds of carriers, this paper introduces the scale invariant feature transform (SIFT) algorithm and video stabilization algorithm based on SIFT features. The motions between images are represented with the model of affine model with six parameters, which is estimated by using the SIFT features of images. Then the images are compensated so that the motions would be counteracted and the goal of stabilizing the video would be achieved. At last, peak signal to noise ratio (PSNR) is imported to evaluate the effect of the algorithm. As the experiments show, algorithm proposed in this paper can counteract the motions among images very well and can improve the values of PSNR effectively. Video stabilization of video sequence is also completed with the algorithm.

  4. Determination of the deuterium abundances in water from 156 to 10,000 ppm by SIFT-MS.

    Science.gov (United States)

    Španěl, Patrik; Shestivska, Violetta; Chippendale, Thomas W E; Smith, David

    2011-01-01

    In response to a need for the measurement of the deuterium (D) abundance in water and aqueous liquids exceeding those previously recommended when using flowing afterglow mass spectrometry (FA-MS) and selected ion flow tube mass spectrometry (SIFT-MS) (i.e. 1000 parts per million, ppm), we have developed the theory of equilibrium isotopic composition of the product ions on which these analytical methods are based to encompass much higher abundances of D in water up to 10,000 ppm (equivalent to 1%). This has involved an understanding of the number density distributions of the H, D, (16)O, (17)O and (18)O isotopes in the isotopologues of H(3)O(+)(H(2)O)(3) hydrated ions (i.e. H(9)O (4) (+) cluster ions) at mass-to-charge ratios (m/z) of 73, 74 and 75, the relative ion number densities of which represent the basis of FA-MS and SIFT-MS analyses of D abundance. Specifically, an extended theory has been developed that accounts for the inclusion of D atoms in the m/z 75 ions, which increasingly occurs as D abundance in the water is increased, and which is used as a reference signal for the m/z 74 ions in the measurement of D abundance. In order to investigate the efficacy of this theory, experimental measurements of deuterium abundance in standard mixtures were made by the SIFT-MS technique using two similar instruments and the results compared with the theory. It is demonstrated that the parameterization of experimental data can be used to formulate a simple calculation algorithm for real-time SIFT-MS measurements of D abundance to an accuracy of 1% below 1000 ppm and degrades to about 2% at 10,000 ppm.

  5. HIV-related cognitive impairment shows bi-directional association with dopamine receptor DRD1 and DRD2 polymorphisms in substance-dependent and substance-independent populations.

    Science.gov (United States)

    Jacobs, Michelle M; Murray, Jacinta; Byrd, Desiree A; Hurd, Yasmin L; Morgello, Susan

    2013-10-01

    It has been postulated that drugs of abuse act synergistically with HIV, leading to increased neurotoxicity and neurocognitive impairment. The CNS impacts of HIV and drug use converge on the mesocorticolimbic dopamine (DA) system, which contains two main receptor subtypes: dopamine receptors 1 (DRD1) and 2 (DRD2). DRD1 and DRD2 have been linked to substance dependence; whether they predict HIV-associated neurocognitive disorder (HAND) is unclear. Using an advanced-stage HIV+ population, we sought to determine if drug dependence impacts the contribution of DA receptor polymorphisms on neurocognition. We observed that both DRD1 and DRD2 polymorphisms were associated with opiate and cocaine dependence (P opiate and cocaine dependency. In the Motor domain, we observed an association for two DRD2 polymorphisms (P < 0.05) in Caucasian subjects. The effects differed for substance dependence groups as the direction of the correlations with DRD2 were opposite to what was seen in subjects without these dependencies. In African-American subjects, associations were observed in nearly every domain, and again, the direction of the correlation differed between substance-dependent and substance-independent groups. We conclude that studies to examine genetic risk for HAND must carefully account for substance dependence patterns when assaying dopaminergic systems, as the neurobiological substrates of cognition in HIV populations may vary with tonic alterations secondary to chronic substance exposures.

  6. 非对称双向多中继系统机会式网络编码中断概率分析%Outage Probability Analysis of Opportunistic Network Coding on Asymmetrical Bi-directional Multi-Relay System

    Institute of Scientific and Technical Information of China (English)

    梁文文; 田华; 徐友云; 许魁; 陈小杰

    2013-01-01

    A practical asymmetrical bi-directional multi-relay system model is firstly constructed, and then an outage probability expression of the model is given based on opportunistic relay scheme and network coding, which is proved accurate by Monte Carlo simulations. Secondly, it analyzes the system average outage probability with different situations of power allocation coefficient, locations of the relay nodes and the number of relay nodes, indicating the inherent relationship between power allocation coefficient and total system power, as well as the number of relay nodes. Simulation results show that the optimal system outage performance of asymmetrical bi-directional multi-relay system based on opportunistic relay scheme and network coding is attained when power allocation coefficient is chosen at 0. 6 or about 0. 6. It can be known that the location of relay nodes is an important factor for the problem of system outage probability.%建立了一个实际的非对称双向多中继系统模型,并采用机会中继策略,推导出了该模型在译码转发方式下采用网络编码时的中断概率表达式,Monte Carlo仿真和理论值吻合,充分验证了该表达式的正确性.分析了不同中继节点位置、不同中继节点个数和不同功率分配因子等情况下的系统中断性能,揭示了最优功率分配因子与中继节点个数和位置以及系统总功率的内在关系.仿真结果表明,在非对称双向多中继系统中同时采用网络编码和机会中继策略时,功率分配因子取值为0.6时可获得最佳的系统中断性能,并指出在研究系统中断概率问题时,中继节点位置是一个不可忽略的因素.

  7. 模块化双向AC/DC变换器并联系统无缝切换控制%Seamless Switching Control for Modular Bi-directional AC/DC Converter Parallel Systems

    Institute of Scientific and Technical Information of China (English)

    张犁; 吴田进; 冯兰兰; 孙凯; 邢岩

    2012-01-01

    研究模块化双向AC/DC变换器并联运行系统,分析指出现有单模块双向运行控制方法引起各并联模块的功率流向不一致的问题;研究系统功率流与直流母线电压变化趋势的内在联系,提出一种模块化AC/DC变换器的双向运行控制方法,分别采用正向和负向电压调节器以保证各并联模块的功率流向一致;整流和逆变状态以不同的直流母线电压运行、自然区分两种功率流向。提出的控制方法可以实现各并联模块整流与逆变之间的无缝切换。详细分析系统稳定性,并指出多模块并联对系统动态特性有所改善;给出关键参数的设计准则。搭建实验验证系统,进行稳态和动态实验。实验结果证明了所提出控制方法的可行性和有效性。%The issue of inconsistent power flow among modular bi-directional AC/DC converters in parallel operation with the conventional control was analyzed.The inherent relationship between system power flow and the trend of the DC bus voltage was researched and a bi-directional operation control for the modular AC/DC converter parallel system was proposed.The consistent power flow of each module is achieved by utilizing a positive and a negative DC bus voltage regulators.Power flows of rectification and inversion are distinguished naturally with different DC bus voltages,and seamless switching between rectification and inversion was also realized.The stability of the modular AC/DC converter parallel system was analyzed in detail with the design principle of the key parameter given.A prototype system was built and both of the steady-state and dynamic experimental results were presented to verify the effectiveness of the proposed system and control method.

  8. Feature description with SIFT, SURF, BRIEF, BRISK, or FREAK? A general question answered for bone age assessment.

    Science.gov (United States)

    Kashif, Muhammad; Deserno, Thomas M; Haak, Daniel; Jonas, Stephan

    2016-01-01

    Solving problems in medical image processing is either generic (being applicable to many problems) or specific (optimized for a certain task). For example, bone age assessment (BAA) on hand radiographs is a frequent but cumbersome task for radiologists. For this problem, many specific solutions have been proposed. However, general-purpose feature descriptors are used in many computer vision applications. Hence, the aim of this study is (i) to compare the five leading keypoint descriptors on BAA, and, in doing so, (ii) presenting a generic approach for a specific task. Two methods for keypoint selection were applied: sparse and dense feature points. For each type, SIFT, SURF, BRIEF, BRISK, and FREAK feature descriptors were extracted within the epiphyseal regions of interest (eROI). Classification was performed using a support vector machine. Reference data (1101 radiographs) of the University of Southern California was used for 5-fold cross-validation. The data was grouped into 30 classes representing the bone age range of 0-18 years. With a mean error of 0.605 years, dense SIFT gave best results and outperforms all published methods. The accuracy was 98.36% within the range of 2 years. Dense SIFT represents a generic method for a specific question.

  9. Spectroscopy by Integration of Frequency and Time Domain Information (SIFT) for Fast Acquisition of High Resolution Dark Spectra

    Science.gov (United States)

    Matsuki, Yoh; Eddy, Matthew T.; Herzfeld, Judith

    2009-01-01

    A simple and effective method, SIFT (Spectroscopy by Integrating Frequency and Time domain information) is introduced for processing non-uniformly sampled multidimensional NMR data. Applying the computationally efficient Gerchberg-Papoulis (G-P) algorithm, used previously in picture processing and medical imaging, SIFT supplements data at non-uniform points in the time domain with the information carried by known “dark” points (i.e. empty regions) in the frequency domain. We demonstrate that this rapid integration not only removes the severe pseudo-noise characteristic of the Fourier transforms of non-uniformly sampled data, but also provides a robust procedure for using frequency information to replace time measurements. The latter can be used to avoid unnecessary sampling in sampling-limited experiments and the former can be used to take advantage of the ability of non-uniformly sampled data to minimize trade-offs between the signal-to-noise ratio and the resolution in sensitivity-limited experiments. Processing 2D and 3D datasets takes about 0.1 and 2 min, respectively, on a personal computer. With these several attractive features, SIFT offers a novel, model-independent, flexible, and user-friendly tool for efficient and accurate processing of multidimensional NMR data. PMID:19284727

  10. Estimating NH3 emissions from agricultural fertilizer application in China using the bi-directional CMAQ model coupled to an agro-ecosystem model

    Science.gov (United States)

    Fu, X.; Wang, S. X.; Ran, L. M.; Pleim, J. E.; Cooter, E.; Bash, J. O.; Benson, V.; Hao, J. M.

    2015-06-01

    Atmospheric ammonia (NH3) plays an important role in atmospheric aerosol chemistry. China is one of the largest NH3 emitting countries with the majority of NH3 emissions coming from agricultural practices, such as fertilizer application and livestock production. The current NH3 emission estimates in China are mainly based on pre-defined emission factors that lack temporal or spatial details, which are needed to accurately predict NH3 emissions. This study provides the first online estimate of NH3 emissions from agricultural fertilizer application in China, using an agricultural fertilizer modeling system which couples a regional air quality model (the Community Multi-scale Air Quality model, or CMAQ) and an agro-ecosystem model (the Environmental Policy Integrated Climate model, or EPIC). This method improves the spatial and temporal resolution of NH3 emissions from this sector. We combined the cropland area data of 14 crops from 2710 counties with the Moderate Resolution Imaging Spectroradiometer (MODIS) land use data to determine the crop distribution. The fertilizer application rates and methods for different crops were collected at provincial or agricultural region levels. The EPIC outputs of daily fertilizer application and soil characteristics were input into the CMAQ model and the hourly NH3 emissions were calculated online with CMAQ running. The estimated agricultural fertilizer NH3 emissions in this study were approximately 3 Tg in 2011. The regions with the highest modeled emission rates are located in the North China Plain. Seasonally, peak ammonia emissions occur from April to July. Compared with previous researches, this study considers an increased number of influencing factors, such as meteorological fields, soil and fertilizer application, and provides improved NH3 emissions with higher spatial and temporal resolution.

  11. Optical Remote Sensing Image Registration Based on SG-SIFT%基于SG-SIFT的光学遥感影像配准

    Institute of Scientific and Technical Information of China (English)

    余先川; 吕中华; 胡丹; 张立保; 徐金东

    2014-01-01

    A new optical remote sensing image registration method signal gridding-scale invariant feature transform ( SG-SIFT) based on signal theory and gridding is proposed. According to relationships among the image layers in the difference of Gaussians scale space, the feature points’ number of each image is set in proportion to make the their distribution uniform in the scale space. In addition, a regular gridding method is introduced to achieve the well distribution of feature points in the image space. Then, error matching pairs are eliminated by a correspondence error checking. Statistical and visual results show that SG-SIFT is superior to standard scale invariant feature transform ( SIFT) according to the feature points distribution, while the number of correct matching pairs from SG-SIFT is 17. 47% more than that of uni-form robust-scale invariant feature transform ( UR-SIFT) in average and the evaluation indicator of root-mean square error confirms its superior performance to SIFT and UR-SIFT.%提出了一种基于信号理论和网格化的尺度不变特征变换( SG-SIFT)光学遥感图像配准算法.根据高斯差分尺度空间中各图像层间的频域关系设定各图像提取特征点的数目,使特征点在尺度域上分布均匀;再将各图像层网格化,使特征点在图像空间中分布均匀;然后用一致性检测法剔除有明显错误的匹配对.实验结果表明,利用SG-SIFT算法得到的特征点比尺度不变特征变换( SIFT)算法的特征点分布更均匀,正确匹配对数目比均匀鲁棒尺度不变特征变换( UR-SIFT)算法均多17.47%,且SG-SIFT算法的均方误差明显低于SIFT和UR-SIFT算法.

  12. 波分复用技术在实现双向改造中的应用%Wavelength Division Multiplexing Technique and its Application in the Realization of Bi-Directional Transformation

    Institute of Scientific and Technical Information of China (English)

    阮邦耀; 陈明希

    2012-01-01

    DWDM和CWDM技术是WDM技术的两种方式,其通过在一芯光纤中传输多路光波来实现光通信网络容量的扩展、提升光信道的利用率。文章通过对DWDM技术优点、技术分类和发展现状的介绍,以及通过对于DWDM和CWDM技术在福州双向网络改造中的应用,来探讨如何在不改变现有光网络结构的基础上,实现网络容量提升,满足用户日益增长的需求。%DWDM and CWDM technology are two ways of WDM technology,through multi-channel optical transmission in a core fiber to achieve upgrading of optical communication network capacity,enhance the utilization of optical channel.This article introduced the DWDM technology advantages,technical classification and the development situation,as well as the DWDM and CWDM technology in Fuzhou bi-directional network transformation application,to explore how to achieve network capacity upgrade and to meet the growing demands of users on the basis of not change the existing optical network structure.

  13. Assessment of mechanical and three-body abrasive wear peculiarity of TiO$_2$- and ZnO-filled bi-directional E-glass fibre-based polyester composites

    Indian Academy of Sciences (India)

    AKANT KUMAR SINGH; SIDDHARTHA; DEEPAK

    2016-08-01

    This paper is about the development of bi-directional E-glass fibre-based polyester composites filled with zinc oxide (ZnO) and titanium dioxide (TiO$_2$) fillers, respectively. The mechanical characterization of these composites is performed. The three-body abrasive wear characteristic of fabricated composites has been assessed under different operating conditions. For this, the three-body abrasion test is done on dry abrasion test rig (TR-50)and analysed using Taguchi’s experimental design scheme and analysis of variance. The results obtained from these experiments are also validated against existing microscopic models of Ratner–Lancaster and Wang. A good linear relationship is obtained between specific wear rate and the reciprocal of ultimate strength and strain at tensile fracture of these composites. It indicates that the experimentally obtained results are in good agreement with theseexisting models. It is found that the tensile strength decreases with filler loading, while hardness, flexural strength, inter-laminar shear strength and impact strength are increased. TiO$_2$-filled composites were observed to performbetter than ZnO-filled composites under abrasive wear situations. The wear mechanism is studied in correlation with the SEM micrograph of the worn-out surface of composites. Performance optimization of composites is doneby using VIKOR method.

  14. Research on a Bi-Directional DC-DC Converter Applied in Electric Vehicle%一种应用于电动汽车的双向DC/DC变换器研究

    Institute of Scientific and Technical Information of China (English)

    陈灵敏

    2009-01-01

    In this paper, topology structures of four non-isolated bi-directional DC/DC converter are analyzed and com-pared. A DC-DC converter-interleaving Buck-Boost is designed aiming at the environment protection and storage battery performance of hybrid electric vehicle(HEV). And the working principle of this converter is presented. The theory is testi-fied through a 3 000 W experiment prototype.%分析和比较了四种非隔离型双向DC/DE变换器的拓扑结构.针对目前广泛使用的混合动力电动汽车存在的环保问题和电池性能问题设计了一种双向DC/DC变换器一两相交错双向DC/DC变换器,论述了其工作原理,并通过一台3 000 W的样机验证了理论的正确性.

  15. The Research on the Bi-Directional Mapping Algorithm between XML and RDB Based on DTD Element-Tress%基于DTD元素树的XML与RDB的双向映射算法研究

    Institute of Scientific and Technical Information of China (English)

    周莉

    2011-01-01

    XML, as the carrier of data exchange between the database, a series of mapping rules by analyzing the mapping principles from the Relational Database to the XML document have been set up, and presented an approach based on DTD Element-Tree and a mapping algorithm between DTD Element-Tress and RDB, Based on this the bi-directional mapping model between the XML document and the RDB is built and a bi-dircetional mapping is given, which is used to complete the data transformation.%分析了XML文档到关系数据库的映射方法,并提出了元素树和元素树节点与其他类型数据之间的映射算法.在此基础上建立了XML模式和关系模式之间的双向映射模型,并给出了双向映射模型算法,从而完成了XML与RDB数据转换.

  16. Demonstration of 575-Mb/s downlink and 225-Mb/s uplink bi-directional SCM-WDM visible light communication using RGB LED and phosphor-based LED.

    Science.gov (United States)

    Wang, Yuanquan; Wang, Yiguang; Chi, Nan; Yu, Jianjun; Shang, Huiliang

    2013-01-14

    We propose and experimentally demonstrate a novel full-duplex bi-directional subcarrier multiplexing (SCM)-wavelength division multiplexing (WDM) visible light communication (VLC) system based on commercially available red-green-blue (RGB) light emitting diode (LED) and phosphor-based LED (P-LED) with 575-Mb/s downstream and 225-Mb/s upstream transmission, employing various modulation orders of quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM). For the downlink, red and green colors/wavelengths are assigned to carry useful information, while blue chip is just kept lighting to maintain the white color illumination, and for the uplink, the low-cost P-LED is implemented. In this demonstration, pre-equalization and post-equalization are also adopted to compensate the severe frequency response of LEDs. Using this scheme, 4-user downlink and 1-user uplink transmission can be achieved. Furthermore, it can support more users by adjusting the bandwidth of each sub-channel. Bit error rates (BERs) of all links are below pre-forward-error-correction (pre-FEC) threshold of 3.8x 10(-3) after 66-cm free-space delivery. The results show that this scheme has great potential in the practical VLC system.

  17. Rolling ball sifting algorithm for the augmented visual inspection of carotid bruit auscultation

    Science.gov (United States)

    Huang, Adam; Lee, Chung-Wei; Liu, Hon-Man

    2016-07-01

    Carotid bruits are systolic sounds associated with turbulent blood flow through atherosclerotic stenosis in the neck. They are audible intermittent high-frequency (above 200 Hz) sounds mixed with background noise and transmitted low-frequency (below 100 Hz) heart sounds that wax and wane periodically. It is a nontrivial task to extract both bruits and heart sounds with high fidelity for further computer-aided auscultation and diagnosis. In this paper we propose a rolling ball sifting algorithm that is capable to filter signals with a sharper frequency selectivity mechanism in the time domain. By rolling two balls (one above and one below the signal) of a suitable radius, the balls are large enough to roll over bruits and yet small enough to ride on heart sound waveforms. The high-frequency bruits can then be extracted according to a tangibility criterion by using the local extrema touched by the balls. Similarly, the low-frequency heart sounds can be acquired by a larger radius. By visualizing the periodicity information of both the extracted heart sounds and bruits, the proposed visual inspection method can potentially improve carotid bruit diagnosis accuracy.

  18. Increased concentrations of breath haloamines are not detectable in airways inflammation using SIFT-MS.

    Science.gov (United States)

    Storer, Malina K; Dummer, Jack D; Cook, Julie; McEwan, Murray; Epton, Michael J

    2011-09-01

    The haloamines, including the chloramines (H(2)NCl, HNCl(2)) and bromamine (H(2)NBr), are diffusible gases that are likely to be produced during inflammation and so may be present as markers of lung inflammation on breath. Although haloamines are quite reactive, it is possible to measure these compounds in humid samples using SIFT-MS. Until recently the quantification of haloamines in breath suffered from interference from other common breath compounds. This was overcome by heating the flow tube which removed major water cluster product ions. Despite the improvements to the method, previous attempts to measure the haloamines in breath samples from normal volunteers had found no evidence to support their presence. Since it is proposed that the haloamines may be present in higher concentrations during airways inflammation we have attempted to detect the compounds in the exhaled breath of patients with airways inflammatory conditions. On-line and off-line breath samples were analyzed; however, there was no discernable change to any of product ions when compared to ambient air or normal subjects. This suggests that despite sensitivity in the mid part per trillion range haloamines are not significantly raised in airways inflammation.

  19. Realization of SIFT Feature Detection Parallel Implementation Based on FPGA%基于FPGA并行处理SIFT算法特征点检测

    Institute of Scientific and Technical Information of China (English)

    薛顺瑞; 高原; 唐湘成; 刘怡; 黄自力

    2012-01-01

    由于SIFT算法计算量大,以至于不能够应用于实时性要求高的领域.为了使SIFT算法满足实时性的需求,详细阐述了SIFT算法中特征点检测与梯度计算硬件实现过程和系统架构,并且对SIFT算法进行相应的改进,使其适合FPGA并行处理特性.最后利用Altera公司Cyclone Ⅲ系列芯片的硬件平台测试SIFT算法硬件部分的计算时间和匹配性能,并且与DSP实现的SIFT算法进行性能上的比较.结果表明,FPGA实现SIFT算法具有实时性高,匹配性能好的特点.%Due to large calculated amount of SIFT algorithm, it is not used in real-time field. In order to the real-time demand for SIFT algorithm. Hardware realization and system architecture that characteristic points detection and calculating pixel's gradient calculation in SIFT algorithm are realized by FPGA is introduced in this paper. And SIFT algorithm is optimized for the parallel processing characteristic of FPGA. Calculating time and matching performance can be test by FPGA IC chip of the Altera Cyclone III series and matching performance can be compared SIFT in FPGA with SIFT in DSP. Finally, FPGA implementation of SIFT algorithm have characteristic of high real-time and matching performance.

  20. Prediction

    CERN Document Server

    Sornette, Didier

    2010-01-01

    This chapter first presents a rather personal view of some different aspects of predictability, going in crescendo from simple linear systems to high-dimensional nonlinear systems with stochastic forcing, which exhibit emergent properties such as phase transitions and regime shifts. Then, a detailed correspondence between the phenomenology of earthquakes, financial crashes and epileptic seizures is offered. The presented statistical evidence provides the substance of a general phase diagram for understanding the many facets of the spatio-temporal organization of these systems. A key insight is to organize the evidence and mechanisms in terms of two summarizing measures: (i) amplitude of disorder or heterogeneity in the system and (ii) level of coupling or interaction strength among the system's components. On the basis of the recently identified remarkable correspondence between earthquakes and seizures, we present detailed information on a class of stochastic point processes that has been found to be particu...

  1. Prior information constrained SIFT matching algorithm for visual simultaneous localization and mapping%视觉同步定位与地图重建——基于先验信息的SIFT匹配算法

    Institute of Scientific and Technical Information of China (English)

    孟旭炯; 蒋荣欣; 陈耀武

    2011-01-01

    鉴于尺度不变特征转换(SIFT)匹配算法存在计算效率不高且容易出现误匹配的问题,针对视觉同步定位与地图重建,提出了一种基于先验信息的SIFT匹配算法.该算法首先根据机器人和特征点的相对距离变化来预测尺度空间的变化;然后根据机器人和特征点的当前状态来预测特征点的图像位置;最后在预测的图像位置进行SIFT匹配.实验结果表明该算法能显著提高SIFT匹配的计算效率和准确性.%The scale invariant feature transform(SIFT) algorithm has the problem of computational inefficiency and mismatch. Therefor, a prior information constrained SIFT matching algorithm is proposed for the visual simultaneous localization and mapping(vSLAM) applications. Firstly, the scale space is predicted according to the relative distance from the robot to the feature. Then the feature position is estimated according to the state of both the robot and the feature. Finally, sift matching is conducted within the predicted image region. The experiment results show that the proposed algorithm can achieve better computational efficiency and matching performance.

  2. 独立光伏发电系统中双向变换器的软起动策略%Two-phase soft start strategy for bi-directional DC-DC converter in solar cell stand-alone photovoltaic power system

    Institute of Scientific and Technical Information of China (English)

    张新华; 廖志凌; 杨孟雄

    2009-01-01

    Bi-directional converter applied to solar cell stand-alone photovoltaic power system belongs to the double sources application. Due to complemented operation of switches in bi-directional converter, traditional soft start method will give rise to large inverse inductor current from the output source at double sources application, and result in damage of converter. This paper proposes a novel soft start method-two-phase soft start method to achieve soft start for bi-directional converter of double sources. By implementing soft start of both active switch and passive switch, two-phase soft start method can realize bi-directional converter soft start at double sources application, avoiding inverse inductor current. Two-phase soft start method applies to a series of bi-directional converter. Experimental results are finally given to verify the effectiveness and validity of two-phase soft start method for bi-directional converter of double sources.%双向变换器在太阳能独立光伏发电系统中属于两端"源"的运用场合,采用传统的软起动方法,由于功率开关管互补导通,会从输出端"源"引入反向电感电流,导致变换器损坏.为了实现双向变换器在两端"源"情况下的开机软起动,提出了一种新颖的双向变换器两段式软起动方法,通过对主控管和被控管实施软起动,避免产生反向电感电流,该方法也适用于一族的双向变换器.最后给出了实验结果,验证了两端"源"双向变换器两段式软起动方法的有效性和正确性.

  3. Implementation of Image Matching Algorithm Based on SIFT Feature%基于SIFT特征的图像匹配算法实现

    Institute of Scientific and Technical Information of China (English)

    王冬; 夏乙; 殷木一; 陈玉林; 李伟; 刘中峰

    2013-01-01

    针对SIFT算法的工程实现问题,详细分析了该算法原理和执行过程.在对SIFT算法原理进行分析时,充分结合Rob Hess的SIFT源代码,并将SIFT算法应用到实际图像的特征提取和匹配中.实验结果表明,SIFT算法提取的特征点对图像缩放、视点变化等具有很好的适应性和准确性,可以应用到图像识别及图像重建等领域.%With the aim to solve the implement problem in scale invariant feature transform(SIFT) algorithm, the theory and the implementation process was analyzed in detail. The characteristics of the SIFT method were analyzed by theory, combined with the explanation of the Rob Hess SIFT source codes. The effect of the SIFT method was validated by matching two different real images. The matching result shows that the features extracted by SIFT method have excellent adaptive and accurate characteristics to image scale, viewpoint change, which are useful for the fields of image recognition, image reconstruction, etc.

  4. Trademark retrieval algorithm based on SIFT feature and corner feature%基于SIFT和角点特征的商标检索算法

    Institute of Scientific and Technical Information of China (English)

    王三虎; 姚望舒; 凌兴宏

    2011-01-01

    针对基于尺度不变特征变换(SIFT)的商标图像检索对于高度相似的反转商标图像容易出现漏检现象,提出了一种基于SIFT和角点特征的商标图像检索方法,该方法利用商标图像的局部角点特征弥补了SIFT特征的不足.实验结果表明,与现有方法相比,该方法保留了SIFT特征对遮挡、扭曲、噪声等干扰具有很强的抵抗力的优点外,同时增强了算法对图像形状的描述能力,表现出了更好的检索能力和性能.%The Scale-Invariant Feature Transform (SIFT) algorithm for trademark retrieval may fail to detect some reversal and highly similar images. To solve this problem, a new algorithm based on SIFT descriptor and corner feature was proposed. This method used corner feature to make up for the lack of SIFT. The experimental results show that this method not only contains the character of SIFT descriptor like robustness against noise, but also improves the ability for description of image shape, so the method shows a better retrieval performance than other methods.

  5. Cascade SIFT Matching Method for Multi-Source SAR Images%应用于多源 SAR 图像匹配的级联 SIFT 算法

    Institute of Scientific and Technical Information of China (English)

    王峰; 尤红建; 傅兴玉; 许宁

    2016-01-01

    This paper presents a cascade SIFT matching method to get large numbers of discrete distributed matches for accurate procedure of multi-source SAR images.Firstly,to obtain more robust matching result,a large scale adapted ani-sotropic Gaussian scale-invariant feature transform ( AAG-SIFT) method is proposed.It is constructed based on large scale AAG scale space, where unstable local textures are blurred, but the structures remain unaffected.Secondly, a local SIFT matching method is recommended which extracts SIFT features from the coarse registered images.And then the features are matched in the local regions to avoid the interferences of the repeated textures from uncorrelated regions.Finally,the priori condition of scale and rotation consistency is used to filter matches,guaranteeing the accuracy of the matching results.Com-pared with traditional matching methods,the proposed method increases the number and distribution quality of the matches, and the location of the matches is accurate.%针对多源SAR( Synthetic Aperture Radar )图像几何精处理需要大量离散控制点的问题,文章中提出一种级联SIFT(Scale Invariant Feature Transform)匹配算法。首先,采用大尺度自适应各向异性高斯SIFT(Adapted Aniso-tropic Gaussian-SIFT,AAG-SIFT)算法进行图像粗配准,大尺度AAG尺度空间可以在模糊不稳定局部纹理干扰的同时,保持图像的结构信息,提高算法的鲁棒性;其次,级联一种局部SIFT匹配算法,在粗配准后图像间进行局部匹配,避免不相关区域内重复纹理对特征匹配的影响;最后,通过尺度和旋转等先验条件筛选匹配点对,保证匹配结果的准确性。对比实验表明,级联SIFT处理可以增加提取同名点的数量和空间分布质量,而且匹配点定位准确。

  6. Differences of Bi-directional Regulative Effects between Acu-moxibustion and Chinese Materia Medica Interventions%针灸和中药双向调节特征之异同

    Institute of Scientific and Technical Information of China (English)

    曹新; 余芝; 徐斌

    2012-01-01

    双向调节是指当机体由于内在或外在因素导致功能亢进或低下时,针灸和中药干预所发挥的平衡效应.通过分析针灸和中药的作用特点,认为针灸和中药的双向调节效应均为多向整体性调节的一种特殊表现,其效应的发挥都与机体的功能状态有关.由于二者治疗性质和作用途径不同,使二者双向效应发挥的基础和模式不同.双向调节是腧穴效应的个性体现,以经络辨证和脏腑辨证为基础;针灸的双向调节效应是多种因素共同作用的结果,其模式以趋中性调节为主.中药双向调节效应的发挥是建立在药证对应的基础上,其调整作用的产生是以所含的拮抗性成分为物质基础,作用模式包括趋中性调节和偏离性调节.%Bi-directional regulation is referred to a balancing effect of both acu-moxibustion and Chinese materia medica interventions when the human body is experiencing a hyperactivity or hypoactivity due to abnormal intrinsic or external factors. In the present paper, the authors analyze their identical and different characteristics from: 1) definitions 2) characters of regulative effects of acu-moxibustion therapy: A) differentiation of meridian and zangfu-organs being the basis of treatment, B) four factors (acupoint-location, body's functional state, acupoint-formula and needle-manipulation techniques) dependant, C) entirety regulation, and D) centrotaxis modulation; 3) characters of Chinese materia medica intervention: including a)correspondence between the drug property and the syndrome being the basis of the regulative effect, b) multi-factors [components (antagonist and agonist) , combination, dosages and processing quality of Chinese materia medica, and functional state of the human body] dependant, c) entirety regulation, and d) both centrotaxis and deviation adjustment. In one word, the bi-directional regulation effect is one of the basic characteristics of both acu-moxibustion and

  7. 适合于混合动力汽车新型双向DC/DC变换器研究%Study of One Bi-directional DC/DC Converter for Hybrid Electric Vehicle

    Institute of Scientific and Technical Information of China (English)

    胡建明

    2011-01-01

    首先介绍了一种混合动力汽车的基本电路,然后根据要求设计了一种双向变换器,它具有高功率传输能力和最小开关应力,适合于连接超级电容器来驱动混合动力汽车.与一些典型的隔离式双向DC/DC变换器相比,该变换器具有较低的设备应力,并且可通过相移加PWM控制,采用隔离变压器的漏感作为能量传输单元和控制变量.最后,实验波形证明该变换器能较好地应用于混合动力汽车.%The paper first introduces the basic drive system of a hybrid electric vehicle.Then the selection and design of aforementioned converter are proposed. The converter has high powerflow capability and minimum device stresses that can suitably interface a super capacitor with the drive train of a hybrid electric vehicle. Furthermore ,by comparing of the main characteristics and applications with some typical isolated bi-directional DC/DC converter, the proposed converter has low device rating and can be controlled by duty cycle and phase shift. At last,the most important characteristics of this converter is to uses the transformer leakage inductance as the primary energy transfer element and control parameters, the experimental waveforms are given to demonstrate the goodness of this novel topology which is in particular for hybrid electric vehicle.

  8. Thermal management and performance evaluation of a dual bi-directional, soft-switched IGBT-based inverter for the 1st autonomous microgrid power system in Taiwan under various operating conditions

    Science.gov (United States)

    Chang, Tien-Chan; Fuh, Yiin-Kuen; Lu, Hong-Yi; Tu, Sheng-Xun

    2016-06-01

    The thermal management of the inverter system is of great importance since very high voltage/current will be switched intermittently and/or continuously and high temperature is excruciably detrimental to the service life of electronics, especially for the switching devices such as insulated gate bipolar transistor (IGBT). In this study, a newly developed dual bi-directional IGBT-based inverter in conjunction with autonomous microgrid system is investigated with particular focus on the thermal management and performance evaluation under various operation conditions. Locally enhanced heat transfer approach such as oblique orientation and heat dissipating materials are experimentally investigated. The studied inverter system is initially packaged by a galvanized steel plate (size 62 × 48 × 18 cm) and the switching power is set in the range of 0.5-3 kW. The module is operated at the switching and pulse frequencies of 60 Hz and 20 kHz, respectively. The adoption of heat dissipating material in either paste or film form had experimentally shown to possess the flexibility tailoring heat transfer performance locally. Experimental studies of heat dissipating film with various hotspot scenarios showed that the temperature difference can be appreciably reduced as much as 13.1 and 15.4 °C, respectively with facilitation of one- and two-layers of heat dissipating film. From the measurement results, the measured peak temperature is highly dominated by the thickness of heat dissipating film, showing the dominance of thickness-dependent thermal resistance and resultant heat accumulation phenomena.

  9. Rapid detection of lipid oxidation in beef muscle packed under modified atmosphere by measuring volatile organic compounds using SIFT-MS.

    Science.gov (United States)

    Olivares, Alicia; Dryahina, Kseniya; Spaněl, Patrik; Flores, Mónica

    2012-12-01

    The objective of this work was to evaluate the use of a direct analysis technique (SIFT-MS) to measure the lipid oxidation process in beef meat packed under high oxygen atmosphere and compare it to conventional techniques such as gas chromatography-mass spectrometry analysis and TBARS values. Meat samples from two suppliers were selected and packaged under the same atmosphere conditions. The fatty acid content, the physicochemical (TBARS and volatile compounds) and sensory parameters were measured. The samples from supplier 2 had a highest content of PUFA and n6 fatty acids that was related with a highest oxidation during storage. SIFT-MS and SPME-GC-MS detected a significant increase for most of the volatiles compounds analyzed during storage especially, in aldehyde compounds. High correlation coefficients between TBARS values and linear aldehydes (C3-C7) measured by both techniques were obtained and this indicates that SIFT-MS can be used to monitor lipid oxidation changes.

  10. Robust SIFT Image Matching Algorithm Based on Unsupervised Learning%基于无监督学习的SIFT鲁棒图像匹配算法

    Institute of Scientific and Technical Information of China (English)

    袭著有

    2014-01-01

    Due to the invariance of scale,rota-tion,illumination,SIFT (scale invariant feature transform)descriptor is commonly used in image matching.However,on the one hand,in practical applications the isolated point and the noise point may cause mismatching points.On the other hand, SIFT feature points record the relationship of dif-ferent scale between the feature point and around it,so easily caused the described similar between the different image feature point and it can be matched each other after extracting their feature points.In order to solve the problem,this paper proposed a feature point matching method based on SIFT algorithm,use unsupervised learning meth-ods to classify the matching points and eliminate the abnormal points,achieving the goal of the sec-ond accurate feature matching.%SIFT特征匹配算法的匹配能力强,但特征点中孤立点和噪声点等会导致部分特征点误匹配;不同图像间特征点的有关描述相近,也会造成两幅不同结构的图像,在提取出各自的 SIFT 特征点后相互匹配。为此,提出一种改进 SIFT 的图像特征匹配算法。该算法是在 SIFT 特征匹配的基础上,利用无监督学习方法对匹配异常点进行剔除,实现特征点的二次精确匹配。

  11. 胃肠调节类中西药对胃肠道平滑肌的双向调节作用%Bi-directional Regulation Effect of Chinese and Western Medicines Used in Gastro-Intestine on Gastro-Intestinal Smooth Muscle

    Institute of Scientific and Technical Information of China (English)

    段煜; 张俊; 战丽彬; 林原; 唐泽耀

    2011-01-01

    在不同条件下,单味、复方中药对胃肠道平滑肌可产生双向调节作用.其可能机理为多层次网络系统的平衡调节等.从整体、离体器官、分子水平,单一、配对西药也对胃肠道平滑肌产生双向调节作用.这种双向调节作用充分体现网络系统平衡调节的整体性的哲学内涵,遵循对立统一规律辩证哲学观.%Chinese traditional sole or compound medicines may affect on gastro- intestinal smooth muscle in bi- directional regulation under different conditions. The possible mechanism may be as the balanced regulation under multi-level network system. Moreover, sole or pair western medicines also can act on the gastro-intestinal smooth muscle in bi-directional regulation in general body or isolated organ or molecular level. The bi-directional regulation fully manifestate the integrity philosophy connotation of balancing regulation in the network system, following dialectical philosophy law of the unity of opposites.

  12. Face recognition method based on DLPP-SIFT%基于直接局部保持投影和尺度不变特征变换的人脸识别方法

    Institute of Scientific and Technical Information of China (English)

    李政仪; 冯贵玉; 赵龙

    2012-01-01

    The Scale Invariant Feature Transform ( SIFT) algorithm is robust to the feature extraction of face image. However, the feature data derived by SIFT is of high dimension, and is difficult to be handled. Therefore, a Direct Locality Preserving Projections-SIFT ( DLPP-SIFT) algorithm was proposed. In the algorithm, SIFT was used to extract feature, and the subspace method with Locality Preserving Projections ( LPP) was utilized for dimension reduction. This algorithm solved locality preserving problem via simultaneous diagonalization; therefore, the singularity of the matrix was avoided. The experiments on ORL and FERET face databases show that the proposed algorithm reduces the computation complexity and matching time of features successfully, and is more robust than SIFT, Principal Component Analysis (PCA) -SIFT and LPP-SIFT methods.%尺度不变特征变换(SIFT)算法提取的人脸特征具有一定的鲁棒性,但存在数据维数过高和计算过于复杂的问题.为此,提出一种基于直接局部保持投影-尺度不变特征变换(DLPP-SIFT)的人脸识别算法.首先采用SIFT算法进行特征提取,然后结合子空间方法局部保持投影(LPP)进行降维,利用直接对角化方法求取特征矩阵,解决了LPP的奇异值问题.在ORL和FERET人脸库的实验结果表明,DLPP-SIFT算法可显著减少计算复杂度和特征匹配时间,与SIFT、主成分分析(PCA)-SIFT、LPP-SIFT相比,具有更好的鲁棒性.

  13. Interactions of timing and prediction error learning.

    Science.gov (United States)

    Kirkpatrick, Kimberly

    2014-01-01

    Timing and prediction error learning have historically been treated as independent processes, but growing evidence has indicated that they are not orthogonal. Timing emerges at the earliest time point when conditioned responses are observed, and temporal variables modulate prediction error learning in both simple conditioning and cue competition paradigms. In addition, prediction errors, through changes in reward magnitude or value alter timing of behavior. Thus, there appears to be a bi-directional interaction between timing and prediction error learning. Modern theories have attempted to integrate the two processes with mixed success. A neurocomputational approach to theory development is espoused, which draws on neurobiological evidence to guide and constrain computational model development. Heuristics for future model development are presented with the goal of sparking new approaches to theory development in the timing and prediction error fields.

  14. 基于CUDA的PCA-SIFT算法研究%Study of PCA-SIFT algorithm based on CUDA

    Institute of Scientific and Technical Information of China (English)

    申昊; 孙永奇

    2012-01-01

    主成分不变特征检测算法PCA-SIFT被广泛应用于图像特征的检测。本文利用最新的图形处理单元(GPU)并行架构和统一计算设备架构(CUDA)灵活的编程性,提出了一种基于CUDA的快速PCA-SIFT特征检测算法。实验结果表明,与CPU架构下的算法相比,本文设计的算法能够在保证特征检测结果不变的情况下获得3-5倍的加速。%The feature detection algorithms based on the principal component invariant PCA-SIFT are widely used in image feature detection. Using the latest graphics processing unit (GPU) and compute unified device architecture (CUDA) which has flexiblility in the programming, a rapid PCA-SIFT feature detection algorithm based on CUDA is designed in this paper. The experimental results show that compared with the algorithm on CPU architecture, the speedup of the algorithm based on CUDA is 3-5 under the condition of the same results of feature detection.

  15. In vitro SIFT-MS validation of a breath fractionating device using a model VOC and ventilation system.

    Science.gov (United States)

    Seeley, Matthew J; Hu, Wan-Ping; Scotter, Jennifer M; Storer, Malina K; Shaw, Geoffrey M

    2009-03-01

    The measurement of volatile organic compounds in exhaled breath is becoming recognized as a method of disease diagnosis and therapeutic monitoring. The aim of this study was to validate the collection of breath from intubated patients in the intensive care setting. This was done by assembling a system of ventilators and humidification to emulate the human respiratory system. A known concentration of acetone was spiked into the system to simulate alveolar and dead-space 'breath'. Selected-ion flow tube mass spectrometry (SIFT-MS) was used to directly measure gas at two separate points (headspace, distal circuit end) and from Tedlar bags collected using a remote breath fractionator. The mean acetone concentration for headspace, distal circuit end and Tedlar bag concentrations were calculated. The fractionator was effective in separating the early (dead space) and late phases of exhaled breath. Results from the late Tedlar bag samples collected by the remote breath fractionator showed a clear correlation with headspace and distal circuit end acetone concentrations. The collection for remote analysis of breath samples from immobile patients is made possible using the breath fractionator in conjunction with SIFT-MS analysis.

  16. 电动汽车与电网互动双向电能检测系统研究%Research on Bi-Directional Power Detection System in the EVs Integrated with Smart Grid

    Institute of Scientific and Technical Information of China (English)

    赵威; 原增泉; 韩华春; 沈彦伶; 许海平

    2014-01-01

    The V2G technology can not only alleviate the power grid voltage and frequency fluctuation caused by renewable energy and improve power grid’s efficiency, but also create benefits for the electric vehicle users. Consequently, the technology of Vehicle to Grid (V2G) is attracting people’s extensive attentions. The significance and the structure of the V2G system have been introduced in this paper. Two new interaction charging strategies of the electric automobile integrated with smart grid have also been introduced briefly, which are the distributed interactive strategy and the centralized interactive strategy. The designing of the bi-directional power detection system in the EVs integrated with smarter grid is mainly discussed. The detection system adopts Logic’s production of the dedicated electric energy metering chip CS5460A, which will provide a high accuracy in data collection, flexibility in control performance and a high cost performance, and is quite suitable for measuring bidirectional power in V2G system. It will make up for the deficiency of DC electric energy measurement system.%通过V2G技术,不仅可以缓解可再生能源引起的电网波动问题,提高电网效率,还可以为电动汽车用户创造收益。因此,V2G(Vehicle to Grid)技术正受到人们的广泛关注,介绍了V2G的意义和系统结构,并简要介绍了电动汽车连接智能电网的两种新型的互动充电策略:分散式互动策略和集中式互动策略。重点介绍了V2G技术中电动汽车与电网互动双向电能检测系统的设计。该检测系统利用了Cirrus Logic公司推出的电能计量专用芯片CS5460A,具有采集数据准确,控制性能灵活且性价比高的优点,适用于V2G系统中的双向电能检测,很好的弥补了市场上直流电能检测设备的不足。

  17. Investigation on Bi-directional SCR ESD Protection Devices in a 0.18 μm RF CMOS Process%0.18 μm RF CMOS双向可控硅ESD防护器件的研究

    Institute of Scientific and Technical Information of China (English)

    柯逸辰; 梁海莲; 顾晓峰; 朱兆旻; 董树荣

    2013-01-01

    Based on the bi-directional silicon controlled rectifier (SCR),two novel electrostatic discharge (ESD) protection devices have been proposed,which can prevent ESD stresses on both the positive and the negative directions.While the conventional dual-direction SCR ESD protection device is usually triggered by the avalanche breakdown between N-well and P-well,the two proposed devices use the embedded NMOS/PMOS as the triggering structure to decrease the trigger voltage.Both the modified structures are implemented in a 0.18 μm RF CMOS process and examined by the transmission line pulse testing system.Experimental results indicate that the proposed devices have lower trigger voltage,smaller leakage current (~nA),a protection level passing 2 kV of human body model,and a high holding voltage (>3.3 V),making them immune to the latch-up in 1.8 V or 3.3 V I/O ESD protection applications.%基于传统双向可控硅(DDSCR)提出了两种静电放电(ESD)保护器件,可应对正、负ESD应力从而在2个方向上对电路进行保护.传统的DDSCR通过N-well与P-well之间的雪崩击穿来触发,而提出的新器件则通过嵌入的NMOS/PMOS来改变触发机制、降低触发电压.两种改进结构均在0.18μm RF CMOS下进行流片,并使用传输线脉冲测试系统进行测试.实验数据表明,这两种新器件具有低触发电压、低漏电流(~nA),抗ESD能力均超过人体模型2 kV,同时具有较高的维持电压(均超过3.3V),可保证其可靠地用于1.8V、3.3 V I/O端口而避免出现闩

  18. Parallel computing method of Monte Carlo criticality calculation based on bi-directional traversal%基于双向遍历的蒙特卡罗临界计算并行方法

    Institute of Scientific and Technical Information of China (English)

    李静; 宋婧; 龙鹏程; 刘鸿飞; 江平

    2015-01-01

    在基于蒙特卡罗粒子输运方法的反应堆模拟中,如裂变堆、聚变裂变混合堆等,达到可接受的统计误差需要大量的计算时间,这已成为蒙特卡罗方法的挑战问题之一,需通过并行计算技术解决。为解决现有方法中通信死锁的问题并保证负载均衡性,设计了基于双向遍历的临界计算并行算法。该方法基于超级蒙特卡罗核计算仿真软件系统SuperMC进行实现,以池式钠冷快堆BN600基准模型进行验证,并与MCNP进行对比。测试结果表明,串行和并行计算结果一致,且SuperMC并行效率高于MCNP。%Background: It requires much computational time with acceptable statistics errors in reactor simulations including fission reactors and fusion-fission hybrid reactors, which has become one challenge of the Monte Carlo method.Purpose: In this paper, an efficient parallel computing method was presented for resolving the communication deadlock and load balancing problem of current methods.Methods: The parallel computing method based on bi-directional traversal of criticality calculation was implemented in super Monte Carlo simulation program (SuperMC) for nuclear and radiation process. The pool-type sodium cooled fast reactor BN600 was proposed for benchmarking and was compared with MCNP.Results: Results showed that the parallel method and un-parallel methods were in agreement with each other.Conclusion: The parallel efficiency of SuperMC is higher than that of MCNP, which demonstrates the accuracy and efficiency of the parallel computing method.

  19. Study on Drag and Sonic Boom of Supersonic Bi-Directional Flying Wing%双向飞翼超声速客机激波阻力和声爆研究

    Institute of Scientific and Technical Information of China (English)

    李占科; 张旭; 冯晓强; 关晓辉

    2014-01-01

    基于超声速双向飞翼构型,采用CFD方法进行阻力计算,采用F-BOOM程序进行声爆计算,研究翼型、平面形状和EFCE激波阻力优化算法对双向飞翼激波阻力和声爆的影响。计算结果表明,平底构型可以明显降低双向飞翼超声速客机的超声速巡航的声爆,却很大程度上增加了巡航阻力,而对称构型却恰好相反;细长的平面几何形状对降低双向飞翼激波阻力和声爆都有作用,尤其对降低对称构型的声爆效果明显;EFCE激波阻力优化算法对降低双向飞翼激波阻力有明显作用,但同时会带来声爆方面的不利影响。因此,超声速客机的减阻设计和低声爆设计需要进行权衡研究。%Based on SBiDir-FW ( supersonic bi-directional flying wing ) , CFD ( Computational Fluid Dynamics ) method is used to calculate the drag and F-BOOM method is applied to compute the sonic boom;this study focuses on how the airfoil, flat shape and EFCE shock wave drag optimization algorithm affect the drag and sonic boom of SBiDir-FW. The results and their analysis show preliminarily that: ( 1 ) flat bottom configuration can reduce the cruise sonic boom of SBiDir-FW remarkably, but it greatly increases the cruising drag, while the opposite phenome-non can be detected in symmetrical configuration;(2)slender flat shape can reduce drag and sonic boom of SBiDir-FW, especially for reducing the sonic boom of symmetrical configuration;(3)EFCE shock wave drag optimization algorithm can reduce the shock wave drag of SBiDir-FW obviously, but will also bring adversely effect on sonic boom. Therefore, the balance should be weighed when considering the design of low drag and low sonic boom for supersonic aircraft.

  20. BI-DIRECTIONAL ANONYMOUS IDENTITY AUTHENTICATION SCHEME FOR CLOUD COMPUTING BASED ON SECURITY ACTIVE BUNDLE%基于安全活跃束S AB的匿名双向云身份认证方案

    Institute of Scientific and Technical Information of China (English)

    张琼文; 吴承荣

    2014-01-01

    Dynamic and transparent cloud brings infinite possibility to people’s life;meanwhile it also imposes greater challenges on theincreasing privacy and security problems of digital identity in virtual world.Digital identity has a close relationship with information services.Before accessing or sharing the resources,the identities of both users and services providers should be authenticated each other.In particular,when the identity theft is rampant,telling authentication on users,partners and cloud services providers is the crucial measurement.Weanalyse the status quo of cloud identity authentication and the challenges encountering,and propose a scheme named “security active bundle(SAB)cloud identity authentication”based on predicate encryption and Active Bundle idea,which realises the bi-directional anonymousauthentication between the end user and the cloud,or among the clouds.This scheme strengthens the privacy protection of personal sensitiveinformation and no longer depends on the trusted third party,etc.%动态透明的云给人们的生活带来了无限的可能,同时也对虚拟世界中与日俱增的数字身份的隐私和安全问题提出了更大的挑战。数字身份和信息服务有着密切关系,在访问或分享资源前,用户和服务双方的身份都有必要先通过认证。特别是当身份窃取猖獗的时候,有力地用户认证、合作伙伴认证、云服务提供商认证等是至关重要的措施。分析云身份认证的现状和面临的挑战,基于谓词加密和Active Bundle思想提出了安全活跃束SAB(Security Active Bundle)云身份认证方案,实现了终端用户与云以及云之间的双向匿名认证,加强了个人敏感信息隐私保护和不再依赖可信第三方等。

  1. 一种基于SIFT特征的快速图像匹配算法%A Fast Image Matching Algorithm Based on SIFT Features

    Institute of Scientific and Technical Information of China (English)

    任忠良

    2015-01-01

    针对SIFT算法运行速度较慢、时间效率不高的问题,本文提出了一种与Harris角点检测算法相结合的快速图像匹配算法。该方法利用Harris角点检测算法计算量小,运行速度快的优点,并改进SIFT算法描述子,通过调整描述子的结构达到特征向量降维的目的,进一步提高算法的时间效率。实验结果证明,该算法既保留了SIFT算法的稳定性以及旋转不变性,也提高了SIFT算法的运行速度。%A new algorithm is proposed combined with Harris corner detection algorithm, in order to improve the efficiency of SIFT which runs slowly and has low efficiency on features extracting. It makes full use of Harris’ low calculation fast operation. By changing the SIFT descriptor, it achieves the goal of decreasing the eigenvector through improving the structure of the descriptor. As the experimental results show, this algorithm, not only retains the stability and rotation invariance of SIFT, but also improves the speed of SIFT algorithm.

  2. Image registration based on SIFT and Krawtchouk moment invariants%结合SIFT和Krawtchouk矩不变量的图像配准方法

    Institute of Scientific and Technical Information of China (English)

    王海凤; 范辉; 李晋江

    2013-01-01

    This paper proposes an image registration based on SIFT( Scale Invariant Feature Transform) and Krawtchouk moment invariants. Key points are extracted from images by applying SIFT. Then Krawtchouk moment invariants from the image region around key point are calculated, and these Krawtchouk moment invariants constitute feature vectors to describe the key point. Finally, key points are matched by calculating the Euclidean distance of feature vectors. The results of experiments show that the algorithm which has the same performance with the standard SIFT is more rapid than the standard SIFT.%提出了一种基于SIFT和Krawtchouk矩不变量的图像配准方法.通过SIFT关键点检测方法检测关键点;对每个关键点计算其邻域的Krawtchouk矩不变量,并将其构成描述关键点的特征向量;计算关键点特征向量之间的欧氏距离找出相匹配的关键点对.实验结果表明,该算法的配准性能与标准SIFT算法相当,而运算速度比标准SIFT算法有较大程度提高.

  3. Area-based stereo matching based on SIFT feature guidance%SIFT特征点引导的区域立体匹配算法

    Institute of Scientific and Technical Information of China (English)

    郭龙源; 孙长银; 杨万扣; 张国云

    2013-01-01

    根据SIFT特征对旋转、尺度缩放、亮度变化保持不变性的特点,提出基于SIFT特征和边缘特征点的区域匹配方法.该方法确定符合SIFT特征的边缘为可靠特征点,并确定其视差;根据视差梯度原理确定其他点的视差,最后生成稠密的视差图.实验结果表明,SIFT特征的引入,提高了特征点视差的准确性,一些弱纹理区的匹配也有所改善.%SIFT features is invariance in zoom, rotate, scale, brightness variations. According to these advantages, this paper presents a novel dense disparity matching algorithm based on the reliable feature points of SIFT and edge region. The method determines SIFT features points in the edge and their disparity; The other points' disparity are determined according to the principle of disparity gradient; A dense disparity map is generated. The experimental results show that the SIFT feature is to improve the accuracy of the disparity of feature points. And the disparity in some weak texture area has also been improved.

  4. 一种结合MSER与SIFT算子的特征检测方法%A Feature Detection Method Combined MSER and SIFT

    Institute of Scientific and Technical Information of China (English)

    莫会宇; 王祝萍

    2011-01-01

    A new method is proposed to extract features under affine transform rapidly. First maximally stable extremal regions(MSER) is detected in the image, then the regions are normalized and extracted by scale-invariant feature transform (SIFT). The experiments show that the method not only gives MSER mathematical description, but also is invariant to affine transforms. Additionally, the method has higher speed than SIFT because it only employ SIFT in maximally stable extremal regions.%为了快速稳定地进行仿射变换下的局部特征区域提取,提出了一种新的特征区域提取算法.首先检测图像最稳定极值区域(MSER),然后将这些区域归一化,接着对其使用尺度不变特征变换(SIFT)算子进行特征提取.试验结果表明,所提出的算法不仅赋予最稳定极值区域合理的数学描述,而且其抗仿射变换能力强于SIFT算子.另外,由于只是对部分图像计算SIFT算子,速度上也要快于传统的SIFT算法.

  5. 基于SIFT匹配的全局运动估计方法%A global motion estimation algorithm based on SIFT matching

    Institute of Scientific and Technical Information of China (English)

    顾广华; 姜思宇; 王成儒

    2011-01-01

    A GME (Global motion estimation) algorithm based on SIFT (Scale invariant feature transform) matching is proposed. For each original SIFT matching key-point, the weighted average gray information of its neighbor area on its scale is first utilized to eliminate the error key-points. The sets of the refining key-points are used to solve the motion model by the least squares method. The proposed method is a new attempt on GME. Experimental results show that the GME method combined with SIFT matching achieves the satisfactory results.%提出了一种基于SIFT(Scale invariant feature transform)匹配的全局运动估计算法.在SIFT初匹配的基础上,对每一个原始匹配特征点,利用所在尺度的邻域灰度信息,对其加权平均后再进行匹配,进而去除误配点.精炼后的匹配点集合作为求解全局运动参数模型的对应数据,采用最小二乘法计算模型参数.在全局运动估计间题上做了一种新的尝试,实验表明,结合SIFT匹配的全局运动估计思路取得了较为满意的效果.

  6. Evaluation of a combination of SIFT-MS and multivariate data analysis for the diagnosis of Mycobacterium bovis in wild badgers.

    Science.gov (United States)

    Spooner, Andrew D; Bessant, Conrad; Turner, Claire; Knobloch, Henri; Chambers, Mark

    2009-09-01

    The currently accepted 'gold standard' tuberculosis (TB) detection method for veterinary applications is that of culturing from a tissue sample post mortem. The test is accurate, but growing Mycobacterium bovis is difficult and the process can take up to 12 weeks to return a diagnosis. In this paper we evaluate a much faster screening approach based on serum headspace analysis using selected ion flow tube mass spectrometry (SIFT-MS). SIFT-MS is a rapid, quantitative gas analysis technique, with sample analysis times of as little as a few seconds. Headspace from above serum samples from wild badgers, captured as part of a randomised trial, was analysed. Multivariate classification algorithms were then employed to extract a simple TB diagnosis from the complex multivariate response provided by the SIFT-MS instrument. This is the first time that such multivariate analysis has been applied to SIFT-MS data. An accuracy of TB discrimination of approximately 88% true positive was achieved which shows promise, but the corresponding false positive rate of 38% indicates that there is more work to do before this approach could replace the culture test. Recommendations for future work that could increase the performance are therefore proposed.

  7. SU-F-303-11: Implementation and Applications of Rapid, SIFT-Based Cine MR Image Binning and Region Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Mazur, T; Wang, Y; Fischer-Valuck, B; Acharya, S; Kashani, R; Li, H; Yang, D; Zoberi, I; Thomas, M; Mutic, S; Li, H [Washington University School of Medicine, St. Louis, MO (United States)

    2015-06-15

    Purpose: To develop a novel and rapid, SIFT-based algorithm for assessing feature motion on cine MR images acquired during MRI-guided radiotherapy treatments. In particular, we apply SIFT descriptors toward both partitioning cine images into respiratory states and tracking regions across frames. Methods: Among a training set of images acquired during a fraction, we densely assign SIFT descriptors to pixels within the images. We cluster these descriptors across all frames in order to produce a dictionary of trackable features. Associating the best-matching descriptors at every frame among the training images to these features, we construct motion traces for the features. We use these traces to define respiratory bins for sorting images in order to facilitate robust pixel-by-pixel tracking. Instead of applying conventional methods for identifying pixel correspondences across frames we utilize a recently-developed algorithm that derives correspondences via a matching objective for SIFT descriptors. Results: We apply these methods to a collection of lung, abdominal, and breast patients. We evaluate the procedure for respiratory binning using target sites exhibiting high-amplitude motion among 20 lung and abdominal patients. In particular, we investigate whether these methods yield minimal variation between images within a bin by perturbing the resulting image distributions among bins. Moreover, we compare the motion between averaged images across respiratory states to 4DCT data for these patients. We evaluate the algorithm for obtaining pixel correspondences between frames by tracking contours among a set of breast patients. As an initial case, we track easily-identifiable edges of lumpectomy cavities that show minimal motion over treatment. Conclusions: These SIFT-based methods reliably extract motion information from cine MR images acquired during patient treatments. While we performed our analysis retrospectively, the algorithm lends itself to prospective motion

  8. A novel SIFt descriptor based on a color quantization matrix%基于颜色量化矩阵的SIFT特征描述方法

    Institute of Scientific and Technical Information of China (English)

    汤伯超; 蔡念; 程昱

    2011-01-01

    In order to avoid the disadvantages of huge computational complexity and poor matching performance in existing scale invariant feature transform(SIFT) descriptors for color images, a novel SIFT descriptor for color images based on color quantization matrix was given. The quantization matrix was obtained by triple-color components. And it was applied to generate a 128-dimensional SIFT descriptor to match color objects. The experimental results showed that, compared with existing SIFT descriptors for color images, this proposed method has the advantages of higher correct matching rate, less matching time and more accurate matching points. This method can effectively match the color objects.%针对现有彩色图像的尺度不变特征转换(scale invariant feature transform,SIFT)算法计算复杂度较大和匹配性能较差的缺点,提出一种基于颜色量化矩阵的SIFT特征描述算法.首先由彩色图像的色调、饱和度和亮度生成颜色量化矩阵,然后由量化矩阵生成128维的SIFT特征描述子,最后应用于彩色目标匹配.实验结果表明,相比于现有彩色图像SIFT算法,本文方法具有匹配正确率高、匹配时间短和正确匹配点数多等优点,能够对彩色目标进行有效地匹配.

  9. 主成分分析法(PCA)在SIFT匹配算法中的应用%Application of PCA Method in SIFT Matching Algorithms

    Institute of Scientific and Technical Information of China (English)

    马莉; 韩燮

    2012-01-01

    An algorithm based on PCA-SIFT feature detection method(Principal Components Analysis-scale invariant keypoints) is introduced into image feature detecting and matching for better real time performance and higher precision. Traditional SIFT method has a large amount of data,and needs long time, PCA-SIFT changed histogram method for main element analysis method, effectively reducing the dimension of the feature descriptor. The extracted feature points are matched with the euclidean distance ratio, and then using the RANSAC algorithm to remove false matching. The experimental results show that the PCA-SIFT algorithm is more stable, more accurate and more rapid.%针对传统SIFT匹配算法数据量大、耗时长的问题,采用了主成分不变特征变换(PCA-SIFT)匹配算法.PCA-SIFT匹配算法将传统SIFT算法中的直方图法换做主元分析法,降低了传统SIFT特征描述符的维数,减少了数据量,提高了匹配效率.首先提取出两幅待匹配图像中的所有特征点及其特征向量,其次将提取出的特征向量采用距离比阈值筛选出匹配点对,再采用RANSAC法消除错配,最后得到精确的匹配结果.实验结果表明,PCA-SIFT算法较稳定、精确、快速.

  10. SIFT - Design and analysis of a fault-tolerant computer for aircraft control. [Software Implemented Fault Tolerant systems

    Science.gov (United States)

    Wensley, J. H.; Lamport, L.; Goldberg, J.; Green, M. W.; Levitt, K. N.; Melliar-Smith, P. M.; Shostak, R. E.; Weinstock, C. B.

    1978-01-01

    SIFT (Software Implemented Fault Tolerance) is an ultrareliable computer for critical aircraft control applications that achieves fault tolerance by the replication of tasks among processing units. The main processing units are off-the-shelf minicomputers, with standard microcomputers serving as the interface to the I/O system. Fault isolation is achieved by using a specially designed redundant bus system to interconnect the processing units. Error detection and analysis and system reconfiguration are performed by software. Iterative tasks are redundantly executed, and the results of each iteration are voted upon before being used. Thus, any single failure in a processing unit or bus can be tolerated with triplication of tasks, and subsequent failures can be tolerated after reconfiguration. Independent execution by separate processors means that the processors need only be loosely synchronized, and a novel fault-tolerant synchronization method is described.

  11. Image matching using SIFT and rotation invariant uniform LTP%基于SIFT和LTP的图像匹配方法

    Institute of Scientific and Technical Information of China (English)

    刘金颂; 张庆阳; 原思聪

    2014-01-01

    针对SIFT算法计算复杂度高,提出了一种SIFT (Scale Invariant Feature Transform)和旋转不变LTP(Local Ternary Pattern)特征相结合的图像匹配方法,以提高SIFT算法的速度.首先利用SIFT算法在两幅需要匹配的图像上分别检测出关键点;然后计算每个关键点周围的旋转不变LTP特征,并作为该关键点的描述子;最后找出两个关键点对之间的匹配点对.实验结果表明,本方法对于图像的匹配性能与SIFT算法相当,运算速度比SIFT算法较快.

  12. Sifting, sorting and saturating data in a grounded theory study of information use by practice nurses: a worked example.

    Science.gov (United States)

    Hoare, Karen J; Mills, Jane; Francis, Karen

    2012-12-01

    The terminology used to analyse data in a grounded theory study can be confusing. Different grounded theorists use a variety of terms which all have similar meanings. In the following study, we use terms adopted by Charmaz including: initial, focused and axial coding. Initial codes are used to analyse data with an emphasis on identifying gerunds, a verb acting as a noun. If initial codes are relevant to the developing theory, they are grouped with similar codes into categories. Categories become saturated when there are no new codes identified in the data. Axial codes are used to link categories together into a grounded theory process. Memo writing accompanies this data sifting and sorting. The following article explains how one initial code became a category providing a worked example of the grounded theory method of constant comparative analysis. The interplay between coding and categorization is facilitated by the constant comparative method.

  13. 双向推力轴承支承结构对润滑性能的影响%Effects of support structure on lubricating properties of bi-directional thrust bearings

    Institute of Scientific and Technical Information of China (English)

    黄滨; 吴军令; 武中德; 焦磊; 王乐勤

    2012-01-01

    为分析水泵水轮机双向推力轴承支承结构对润滑性能的影响,建立了推力轴承的三维热弹流动力润滑数学模型,并给出了合理的边界条件.分别通过有限差分法和大型有限元软件Ansys1 1.0求解热流体动力润滑模型和瓦块的热弹变形,二者之间的数据传递通过自编接口自动实现.将文中所建立的计算模型应用于算例分析,得到额定工况下的油膜厚度、油膜压力和瓦块温度分布情况,通过对理论计算结果和试验测量结果对比发现两者吻合较好.在此基础上分析了3种不同支承结构下的轴承静特性分布和瓦面热弹变形分布趋势.结果表明:选择合理的支承结构将明显提高轴承的润滑性能,条形支承结构和双托盘支承结构的瓦面热弹变形分布比单托盘支承结构更加合理,因此润滑性能要明显优于单托盘支承结构.%A three-dimensional thermo-elastic-hydrodynamic mathematical model of thrust bearing was set up and the boundary conditions was adopted for analysis of the effects of support structure on hydrodynamic lubrication performance of bi-directional thrust bearing in pump-turbine. The finite difference method was employed to solve the THD model, and the thermal-elastic deformations in the pad were obtained by the finite element software ANSYS11.0. The data transfer between the THD model and ANSYS11.0 was carried out automatically by an interface program. The calculation model set up in this paper was then applied to a calculating example. The oil film thickness distribution, oil film pressure distribution and pad temperature distribution were obtained. Good agreement between the theoretical calculating results and experimental test was obtained. On this basis, the static performance distribution and thermo-elastic deformation distribution on the pad surface of three different support disks were analyzed. The results show that improving lubricant performance can be obtained if

  14. Stability analysis of cross sea tunnel with shock absorption subjected to seepage and bi-directional earthquake%渗流和双向地震下跨海减震隧道的稳定分析

    Institute of Scientific and Technical Information of China (English)

    程选生; 俞东江; 刘博; 徐伟伟; 林梅

    2016-01-01

    In order to study the structural stability of sea-crossing shock absorption tunnel subjected to the ac-tions of seepage and bidirectional earthquake,dynamic finite element static strength reduction method was used, and the structure field and fluid field models were established using ADINAsoftware in this paper,respective-ly.Considered factors included the effect of viscoelastic artificial boundary,seepage and bidirectional earth-quake,the influences of dynamic stability on the water depth,the thickness of overlying rock and the coefficient of permeability with shock absorption layer of cross sea tunnel as well as the transition law of plastic zone were studied.The results show that when subjected to the action of seepage and bi -directional earthquake,plastic zone of cross sea tunnel with shock absorption first appears at two arch feet and peripheral parts of arch shoulder, while it doesn’t appear at the arch top.The thicker the overlying rock is,the less improvement in seismic safety factor the shock absorption layer results in.The varying sea water depth and the coefficient of permeability have little effect on the safety factor when shock absorption layer is used.The overlying rock thickness makes greater influence on the safety coefficient of the tunnel when subjected to seepage and bidirectional earthquake than the water depth and the coefficient of permeability.%为了研究渗流和双向地震作用下跨海减震隧道工程结构的稳定性,采用动力有限元静力强度折减法,并利用ADI-NA软件分别建立了结构场和流体场分析模型。考虑黏弹性人工边界、双向地震和渗流的影响,研究海水深度、覆岩厚度和渗透系数对设置减震层跨海隧道动力稳定安全系数的影响以及塑性区的变化规律。研究结果表明:渗流和双向地震作用下,跨海减震隧道结构的塑性区最先出现在隧道结构的两侧拱脚和拱肩周边部位,拱顶部位没有出现塑形区

  15. Modality prediction of biomedical literature images using multimodal feature representation

    Directory of Open Access Journals (Sweden)

    Pelka, Obioma

    2016-08-01

    Full Text Available This paper presents the modelling approaches performed to automatically predict the modality of images found in biomedical literature. Various state-of-the-art visual features such as Bag-of-Keypoints computed with dense SIFT descriptors, texture features and Joint Composite Descriptors were used for visual image representation. Text representation was obtained by vector quantisation on a Bag-of-Words dictionary generated using attribute importance derived from a χ-test. Computing the principal components separately on each feature, dimension reduction as well as computational load reduction was achieved. Various multiple feature fusions were adopted to supplement visual image information with corresponding text information. The improvement obtained when using multimodal features vs. visual or text features was detected, analysed and evaluated. Random Forest models with 100 to 500 deep trees grown by resampling, a multi class linear kernel SVM with C=0.05 and a late fusion of the two classifiers were used for modality prediction. A Random Forest classifier achieved a higher accuracy and computed Bag-of-Keypoints with dense SIFT descriptors proved to be a better approach than with Lowe SIFT.

  16. 基于空间变换迭代的SIFT特征图像匹配算法%SIFT matching algorithm with geometry constraint

    Institute of Scientific and Technical Information of China (English)

    杨新锋; 滕书华; 夏东

    2013-01-01

    For the rotation, translation, scale invariant properties of SIFT (Scale Invariant Feature Transform) feature, it has been widely applied in imaging matching. But there are two defects of using SIFT while matching. Firstly, the matching performance is directly affected by the matching parameters, and there is always mismatching and error matching existed. Secondly, it only fits for matching under similarity transformation, while at the affine transformation situation it fails. In this paper, a novel iterative matching algorithm based on transformation estimation was proposed. The SIFT matching problem was turned into an optimization problem about SIFT feature vector and the geometry distribution of the point sets. By searching for the affine transformation and correspondences under the iterative deterministic annealing frame, the algorithm got the optimal matching result of SIFT point sets. Experiment results show that even at large affine transformation, the algorithm can still get the right matching results.%SIFT(Scale Invariant Feature Transform)特征由于具有旋转、平移和尺度不变性在图像匹配中得到了广泛的应用。但直接运用SIFT特征进行匹配,存在两个问题:易受匹配参数的影响,出现较多的错漏匹配现象;只适用于相似变换情况下的图像匹配,对于高维的仿射变换情况则难以奏效,而在实际图像匹配中这种情况更为常见。针对以上问题,提出了一种空间变换迭代的SIFT特征图像匹配方法。把SIFT特征点集匹配转化为SIFT特征向量与点集的几何分布信息相关的函数最优化求解问题,通过在确定性退火框架下,迭代求解空间仿射变换与点集匹配对应关系,最终得到最优的SIFT特征点匹配关系。仿真实验表明:在较大仿射变换情况下该方法仍能实现图像SIFT特征点集的正确匹配。

  17. 基于PDCRAN-SIFT的特征匹配技术研究%Research on Features Matching Based on PDCRAN-SIFT Algorithm

    Institute of Scientific and Technical Information of China (English)

    王碧璇; 张科; 宋军艳

    2013-01-01

    研究复杂背景下图像的目标识别,提高复杂背景下识别攻击目标的准确性和快速性.针对SIFT特征具有冗余度高、可分性差的缺点,提出PDCRAN-SIFT的方法对SIFT特征进行聚类精选,首先引入概率距离聚类的方法对SIFT特征进行聚类,选取每一类的代表特征向量作为粗聚类特征向量,然后运用随机采样一致算法剔除粗聚类特征向量中与目标图像误匹配的特征向量,从而得到精聚类匹配特征向量.实验表明,经过处理之后的PDCRAN-SIFT特征向量,冗余度大大减小,匹配时间缩短了50%左右,特征可分性和对光照、视角、噪声的鲁棒性也比SIFT特征明显增强.%This paper researches image object recognition in cluttered background to improve the accuracy and speediness of battlefield target identification.With SIFT's defects of redundancy and weak,this paper presents a PDCRAN-SIFT algorithm to improve SIFT features.First,the probabilistic distance clustering (PDC) algorithm is used to cluster the redundancy of SIFT features,select the represent features as coarse features.Then,the mismatching features are rejected by Random Sample Consensus (RANSAC) method,obtaining the refined matching features.The experiment results show the refined matching features have reduced SIFT features'redundancy to a great extent,the matching time is shortened by about 50%.What's more,they are easier to distinguish and more robust than SIFT's for light variation,rotation changes and adding noise.

  18. 基于SIFT特征与区域相结合的双目视觉匹配算法%BINOCULAR VISION MATCHING ALGORITHM BASED ON COMBINATION OF SIFT FEATURES AND AREA

    Institute of Scientific and Technical Information of China (English)

    黄向东; 姬智华

    2014-01-01

    SIFT feature has features of keeping invariance against the variations in rotation,size scaling and brightness,considering these features,we use binocular vision system to collect stereo image pairs from two different vision angles,and propose a matching algorithm which is based on the combination of SIFT feature matching and improved area matching.The method determines the edge conforming to SIFT features as the reliable feature point and determines its parallax;the parallaxes of other points are determined according to parallax gradient principle,and finally the dense disparity map is then generated.Experimental results show that the introduction of matching algorithm combining the SIFT features and area improves the accuracy of the parallax of feature point,the matching of some weak texture areas is also improved.%以 SIFT 特征对旋转、尺度缩放、亮度变化保持不变性的特点,使用双目视觉系统从两个不同的视觉角度采集立体图像对,提出基于 SIFT 特征匹配和改进的区域匹配相结合的匹配算法。该方法确定符合 SIFT 特征的边缘为可靠特征点,并确定其视差;根据视差梯度原理确定其他点的视差,最后生成稠密的视差图。实验结果表明,SIFT 特征与区域相结合的匹配算法的引入,提高了特征点视差的准确性,一些弱纹理区的匹配也有所改善。

  19. 基于PLC控制的铝粉自动过筛和称量系统%The Aluminium Powder Automatically Sifting and Weighing System Based on PLC

    Institute of Scientific and Technical Information of China (English)

    曾庆林; 邹庆勇

    2011-01-01

    本文闸述了一套基于PLC控制的铝粉自动过筛和称量系统,该系统基于西门子PLC和工业控制计算机控制,采用现场总线技术,实现了铝粉过筛和称量的远程隔离操作,提高了工作效率,保障了操作人员的身体健康和生命安全.%The article describes an aluminium powder automatically sifting and weighing system based on PLC control. The system is based on Siemens PLC and industrial control computer control, and uses field-bus technology. In the system, the aluminum powder is sifted and weighed in distance. It improves working efficiency, protects the operator's health and safety.

  20. LDA-based SIFT algorithm and its application in image registration%基于LDA的SIFT算法在图像配准中的应用

    Institute of Scientific and Technical Information of China (English)

    丁湘楠; 谢正忠; 宋晓宁

    2013-01-01

    针对SIFT算法复杂程度高,实时性差,在维数较高的图像配准中并不实用的问题,提出了一种基于线性鉴别分析(LDA)的SIFT算法(SIFT-LDA).首先利用SIFT算法提取出图像的特征点向量,然后用LDA方法对其进行特征抽取并降维.通过高维自然图像和单幅人脸图像进行实验,实验结果表明SIFT-LDA算法在保证匹配精度的同时,实时性要优于传统的SIFT算法,其匹配时间相对于传统SIFT算法缩短了将近一半.

  1. 基于SSON文档树的NoSQL数据库与关系数据库双向映射算法研究%The Research on the Bi-Directional Mapping Algorithm between NoSQL Database and RDB Based on BSON Document-Tree

    Institute of Scientific and Technical Information of China (English)

    周莉

    2016-01-01

    Analyzed SSON document's structure,the concept and structure of SSON Document-Tree is given by comparing methods of analogy,and the mapping strategy from NoSQL document database to relational database has been presented. Sased on this,the bi-directional mapping model between the documents in NoSQL database and the RDS schema is built and a bi-directional algorithm is given.%分析了SSON文档的结构,通过比较类似结构的映射方法,给出了SSON文档树的概念和结构,并提出NoSQL数据库文档到关系数据库的映射策略,在此基础上建立了SSON文档模式和关系模式之间的双向映射模型,并给出了双向映射算法。

  2. SIFT Feature Detection and Matching Based on Salient Map%基于显著图的SIFT特征检测与匹配

    Institute of Scientific and Technical Information of China (English)

    尹春霞; 徐德; 李成荣; 罗杨宇

    2012-01-01

    基于尺度不变特征变换(SIFT)特征的图像匹配存在特征点数量大、运算时间长等问题.为此,引入视觉注意机制,提出一种基于显著图的SIFT特征检测与匹配方法.比较常用的显著图计算模型,选择谱残差方法提取图片的显著图.对显著图进行二值化和形态学等处理,得到规则合理的显著区域.在显著区域内提取SIFT特征,生成特征向量,进行图像匹配.实验结果表明,该方法能提高运算效率,并且得到的SIFT特征更加稳定.%Image matching based on Scale Invariant Feature Transform(SIFT) feature is time-consuming, and there are always a large number of feature points. By introducing salient map into feature extraction and image matching, a new SIFT feature detection and matching method is put forward. Salient computing models are compared, and an efficient spectral residual method is selected to compute the salient map. Then the salient map is processed with binarization and morphology to get regular salient area. SIFT features are detected and matched just in the salient area instead of in the whole image. Experimental results show that the proposed method is much faster and the features in salient area are more stable.

  3. 基于Harris-SIFT算法的双目立体视觉定位%Object Location Technique for Binocular Stereo Vision Based on Harris-SIFT Algorithm

    Institute of Scientific and Technical Information of China (English)

    李耀云; 贾敏智

    2013-01-01

    针对基于尺度空间对图象保持不变性的SIFT算法在双目立体视觉应用时实时性差、误匹配等问题,提出一种运用Harris-SIFT算法进行双目立体视觉定位方法.通过介绍双目立体视觉的模型原理,利用Harris-SIFT算法从左右摄像机分别获取的图像中检测目标,并获取匹配目标的特征点,对两幅图像中目标物体的坐标标定,通过计算可得到目标物体的深度距离,还原其三维信息.实验证明,运用Harris-SIFT算法使该系统的实时性能和距离精度得到提高.%The object location technique for binocular stereo vision has some problems of the poor real-time performance and the mismatching based on the SIFT algorithm of the scale space to image keep invariance.A method of the object location technique for binocular stereo vision developed based on the Harris-SIFT algorithm is presented.Through the introduction of the binocular stereo vision model principle,adopting new Harris-SIFT algorithm to get the camera image form the two detection target,and for matching the feature points of the target,according to the target object coordinate calibration two images of the two images.Through the calculation can get the depth of the object distance,reducing the 3d information.The experiments improve the real-time performance and the accuracy distance based on the Harris-SIFT algorithm.

  4. LAN Shishuang, SUN Jinguang. Geometrical attack digital watermarking based on improved SIFT.%基于改进SIFT的抗几何攻击的数字水印

    Institute of Scientific and Technical Information of China (English)

    兰世爽; 孙劲光

    2011-01-01

    An effective against geometric attack robustness of digital watermarking algorithm based on improved SIFT(Scale Invariant Feature Transform) is presented. It achieves watermark synchronization using improved Scale-Invariant Feature Transform; watermark is embedded in cirque,using odd-even quantization in spatial domain and is extracted from an odd-even detector. Simulation results show that improved SIFT can reduce the matching dimension of feature point, improve the matching rate. And the proposed scheme achieves good image quality and it is robust to geometric attacks as well as traditional signal operations.%通过改进的SIFT(尺度不变特征变换)算法提出了一种可有效抵抗几何攻击的鲁棒数字水印算法.此算法利用改进的SIFT进行水印信号的同步;水印嵌入采用圆环的嵌入模式,在空域以奇偶量化形式嵌入;通过奇偶检测器提取水印.实验结果表明,改进的SIFT大大降低特征点匹配的维数,提高匹配速率,同时该算法能获得很好的图像质量,能有效抵抗几何攻击和常规的信号处理攻击.

  5. SIFT assisted fast harris image match algorithm%SIFT辅助角点匹配的快速图像匹配算法

    Institute of Scientific and Technical Information of China (English)

    封泽希; 张辉; 丁清; 朱敏

    2011-01-01

    采用Harris角点检测算法进行图像特征检测.使用快速SIFT图像匹配方法进行图像匹配并计算基础矩阵,去除误匹配点后用SIFT图像匹配的结果对Harris角点进行定位,并用ZNCC算法对角点进行增量匹配.该算法有效地弥补了SIFT图像匹配算法的特征点只分布于非边缘区域的问题,相比单纯SIFT算法可获得更多的匹配点,并且算法时间增加较少.%This method used Harris corner detection algorithm for image feature detection.Using fast SIFT algorithm to get the initial match points, this method computed the fundamental matrix to remove error matches, then incrementally locate candidates feature points and match them with ZNCC algorithm.This method compensate the shortcomings that the SIFT algorithm computed no edge feature points, and can get more matched points compare to using the SIFT algorithm itself while algorithm's computing time increases little.

  6. Detecting volatile compounds from Kraft lignin degradation in the headspace of microbial cultures by selected ion flow tube mass spectrometry (SIFT-MS).

    Science.gov (United States)

    Gibson, Andrew; Malek, Lada; Dekker, Robert F H; Ross, Brian

    2015-05-01

    Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) was used to quantify methanol and other volatile compounds in the headspace of one bacterial and 12 fungal lignin-degrading microbial cultures. Cultures were grown in 250 mL Erlenmeyer flasks capped with aluminum foil containing 40 mL of nutrient media using Kraft lignin (0.3% w/v) as the sole carbon source. Analysis was done using SIFT-MS with H3O(+) and NO(+) precursors. Product ions were identified with multiple ion mode (MIM). Full scan (FS) mode was used to identify other compounds of interest. Absidia cylindrospora, Ischnoderma resinosum and Pholiota aurivella increased headspace methanol concentration by 136 ppb, 1196 ppb and 278 ppb, respectively, while Flammulina velutipes and Laetiporus sulphureus decreased concentration below ambient levels. F. velutipes and L. sulphureus were found to produce products of methanol oxidation (formaldehyde and formic acid) and were likely metabolizing methanol. Some additional unidentified compounds generated by the fungal cultures are intriguing and will require further study. SIFT-MS can be used to quantify methanol and other volatile compounds in the headspace of microbial cultures and has the potential to be a rapid, sensitive, non-invasive tool useful in elucidating the mechanisms of lignin degradative pathways.

  7. Entropy-Based and Weighted Selective SIFT Clustering as an Energy Aware Framework for Supervised Visual Recognition of Man-Made Structures

    Directory of Open Access Journals (Sweden)

    Ayman El Mobacher

    2013-01-01

    Full Text Available Using local invariant features has been proven by published literature to be powerful for image processing and pattern recognition tasks. However, in energy aware environments, these invariant features would not scale easily because of their computational requirements. Motivated to find an efficient building recognition algorithm based on scale invariant feature transform (SIFT keypoints, we present in this paper uSee, a supervised learning framework which exploits the symmetrical and repetitive structural patterns in buildings to identify subsets of relevant clusters formed by these keypoints. Once an image is captured by a smart phone, uSee preprocesses it using variations in gradient angle- and entropy-based measures before extracting the building signature and comparing its representative SIFT keypoints against a repository of building images. Experimental results on 2 different databases confirm the effectiveness of uSee in delivering, at a greatly reduced computational cost, the high matching scores for building recognition that local descriptors can achieve. With only 14.3% of image SIFT keypoints, uSee exceeded prior literature results by achieving an accuracy of 99.1% on the Zurich Building Database with no manual rotation; thus saving significantly on the computational requirements of the task at hand.

  8. 一种改进的SIFT描述子及其性能分析%An Improved SIFT Descriptor and Its Performance Analysis

    Institute of Scientific and Technical Information of China (English)

    唐朝伟; 肖健; 邵艳清; 苗光胜

    2012-01-01

    In order to solve the problems that conventional SIFT descriptors result in a lot mismatches when an image has many similar regions,an improved SIFT Descriptor and its generation method are proposed.Firstly,the steps of constructing scale space,detecting extrema and confirming keypoints are employed to create the key feature points.Secondly,each keypoint is described by the rotation-invariant Texture patterns,which are computed from the image patch centered at the keypoint,and be combined to SIFT feature to construct the union feature.Finally,a rotation invariant textured SIFT descriptor is formed.Two different matching strategies are adopted as the method applied to image matching.The experiment show that the method makes the image content information more comprehensive,it enhances the accuracy of matching and improves matching results greatly,achieve the improvement of SIFT algorithm.%为了解决传统SIFT描述子在图像存在多个相似区域时易造成误匹配的问题,提出了一种改进的SIFT描述子及其生成方法。该方法通过构建尺度空间、检测极值点、确定关键点等步骤生成关键特征点,然后计算每个关键点周围图像区域的旋转不变纹理特征作为该关键点的描述,并将其融合到局部特性SIFT描述向量中,形成旋转不变纹理化SIFT描述子,并采用了两种不同的匹配策略应用于图像匹配,实验结果表明,本方法更加全面地描述了图像信息,有效提高了SIFT算法匹配准率,改善了匹配效果,实现了对SIFT算法的改良。

  9. 基于SIFT的抗几何攻击水印研究与实现%Watermark Research and Implementation Against Geometric Distortion Based on SIFT

    Institute of Scientific and Technical Information of China (English)

    张斌; 王嘉祯; 文家福; 常雷

    2011-01-01

    数字水印算法面临几何攻击时,往往丢失了水印嵌入与水印检测的同步性,造成水印算法的彻底失效,而基于特征点的水印算法能够较好地抵抗几何扭曲的攻击,特别是基于最新的旋转、缩放、平移不变的SIFT特征点的数字水印算法,在抵抗几何攻击的同时,能够较好地抵抗光照,视角等变化.在分析SIFT特征点选取原理的基础上,指出了该方法的优势及能够抵抗RST攻击的本质原因,对其算法进行了matlab优化实现,并提出了基于SIFT的抗几何攻击的数字水印方案,此外,给出了图像特征点的一般定义,讨论了水印特征点选取一般和理想要求.%When digital watermark meets geometric attack, generally the synchronization between the embedding and extraction of the watermark is lost, which means the watermark algorithm is useless. The algorithm based image features can better resist geometric distortion, especially the algorithm based on SIFT. SIFT is not only can resist PST, but also can resist the change of the illumination and viewpoint. Based on the principle analysis of SIFT, introduce the key reasons that SIFT can endure RST distortion, then give out the implementation using Matlab program, and propose a digital watermark scheme which can endure PST attack based on SIFT, by the way,propose a general definition for image special points, and discuss the general and idle requirement for digital watermark special points.

  10. SUPER-RESOLUTION AND DE-CONVOLUTION FOR SINGLE/MULTI GRAY SCALE IMAGES USING SIFT ALGORITHM

    Directory of Open Access Journals (Sweden)

    Ritu Soni

    2015-10-01

    Full Text Available This paper represent a Blind algorithm that restore the blurred images for single image and multi-image blur de-convolution and multi-image super-resolution on low-resolution images deteriorated by additive white Gaussian noise ,the aliasing and linear space-invariant. Image De-blurring is a field of Image Processing in which recovering an original and sharp image from a corrupted image. Proposed method is based on alternating minimization algorithm with respect to unidentified blurs and high-resolution image and the Huber-markov random field(HMRF model for its ability to preserve discontinuities of a image and used for the regularization that exploits the piecewise smooth nature of the HR image. SIFT algorithm is used for feature extraction in a image and produce matching features based on Euclidean distance of their feature vectors that help in calculation of PSF. For blur estimation, edge-emphasizing smoothing operation is used to improve the quality of blur by enhancing the strong soft edges. In filter domain the blur estimation process can be done rather than the pixel domain for better performance that means which uses the gradient of HR and LR images for better performance.

  11. Recent Selected Ion Flow Tube (SIFT) Studies Concerning the Formation of Amino Acids in the Gas Phase

    Science.gov (United States)

    Jackson, Douglas M.; Adams, Nigel G.; Babcock, Lucia M.

    2006-01-01

    Recently the simplest amino acid, glycine, has been detected in interstellar clouds, ISC, although this has since been contested. In order to substantiate either of these claims, plausible routes to amino acids need to be investigated. For gas phase synthesis, the SIFT technique has been employed to study simple amino acids via ion-molecule reactions of several ions of interstellar interest with methylamine, ethylamine, formic acid, acetic acid, and methyl formate. Carboxylic acid type ions were considered in the reactions involving the amines. In reactions where the carboxylic acid and methyl formate neutrals were studied, the reactant ions were primarily amine ion fragments. It was observed that the amines and acids preferentially fragment or accept a proton whenever energetically possible. NH3(+), however, uniquely reacted with the neutrals via atom abstraction to form NH4(+). These studies yielded a body of data relevant to astrochemistry, supplementing the available literature. However, the search for gas phase routes to amino acids using conventional molecules has been frustrated. Our most recent research investigates the fragmentation patterns of several amino acids and several possible routes have been suggested for future study.

  12. Tracking features in retinal images of adaptive optics confocal scanning laser ophthalmoscope using KLT-SIFT algorithm.

    Science.gov (United States)

    Li, Hao; Lu, Jing; Shi, Guohua; Zhang, Yudong

    2010-06-28

    With the use of adaptive optics (AO), high-resolution microscopic imaging of living human retina in the single cell level has been achieved. In an adaptive optics confocal scanning laser ophthalmoscope (AOSLO) system, with a small field size (about 1 degree, 280 μm), the motion of the eye severely affects the stabilization of the real-time video images and results in significant distortions of the retina images. In this paper, Scale-Invariant Feature Transform (SIFT) is used to abstract stable point features from the retina images. Kanade-Lucas-Tomasi(KLT) algorithm is applied to track the features. With the tracked features, the image distortion in each frame is removed by the second-order polynomial transformation, and 10 successive frames are co-added to enhance the image quality. Features of special interest in an image can also be selected manually and tracked by KLT. A point on a cone is selected manually, and the cone is tracked from frame to frame.

  13. Comparison of tomatillo and tomato volatile compounds in the headspace by selected ion flow tube mass spectrometry (SIFT-MS).

    Science.gov (United States)

    Xu, Yichi; Barringer, Sheryl

    2010-04-01

    The concentration of 31 volatiles were measured in the headspace of tomatillos using selected ion flow tube-mass spectrometry (SIFT-MS), and were compared with those in vine-ripened tomato, roma tomato, cherry tomato, and grape tomato. None of the volatiles were higher in the headspace of tomatillos than of tomatoes. Compounds (E)-2-octenal, (E)-2-pentenal, 2-isobutylthiazole, 6-methyl-5-hepten-2-one, and phenylacetaldehyde were significantly lower in tomatillo than in the tomato varieties in the headspace. After blending, volatiles in the headspace increased, and then decreased after reaching a maximum concentration, due to further degradation or depletion. Compounds (E)-2-pentenal and 1-penten-3-one reached a maximum concentration later than (E)-2-hexenal, (Z)-3-hexenal, and hexanal for tomatillo and tomatoes. The slope of the ratio of (E)-2-hexenal and (Z)-3-hexenal was not significantly different for any of the samples, implying that the activity of cis/trans isomerase was not different between tomatillos and tomatoes.

  14. Reading and proclaiming the Advent call of John the Baptist: An empirical enquiry employing the SIFT method

    Directory of Open Access Journals (Sweden)

    Leslie J. Francis

    2014-02-01

    Full Text Available Drawing on Jungian psychological type theory, the SIFT method of biblical hermeneutics and liturgical preaching suggests that the reading and proclaiming of scripture reflects the psychological type preferences of the reader and preacher. This thesis is examined among a sample of clergy (training incumbents and curates serving in the one Diocese of the Church of England (N = 22. After completing the Myers-Briggs Type Indicator, the clergy worked in groups (designed to cluster individuals who shared similar psychological type characteristics to reflect on and to discuss the Advent call of John the Baptist. The Marcan account was chosen for the exercise exploring the perceiving functions (sensing and intuition in light of its rich narrative. The Lucan account was chosen for the exercise exploring the judging functions (thinking and feeling in light of the challenges offered by the passage. In accordance with the theory, the data confirmed characteristic differences between the approaches of sensing types and intuitive types, and between the approaches of thinking types and feeling types.

  15. Reading and proclaiming the Advent call of John the Baptist: An empirical enquiry employing the SIFT method

    Directory of Open Access Journals (Sweden)

    Leslie J. Francis

    2014-10-01

    Full Text Available Drawing on Jungian psychological type theory, the SIFT method of biblical hermeneutics and liturgical preaching suggests that the reading and proclaiming of scripture reflects the psychological type preferences of the reader and preacher. This thesis is examined among a sample of clergy (training incumbents and curates serving in the one Diocese of the Church of England (N = 22. After completing the Myers-Briggs Type Indicator, the clergy worked in groups (designed to cluster individuals who shared similar psychological type characteristics to reflect on and to discuss the Advent call of John the Baptist. The Marcan account was chosen for the exercise exploring the perceiving functions (sensing and intuition in light of its rich narrative. The Lucan account was chosen for the exercise exploring the judging functions (thinking and feeling in light of the challenges offered by the passage. In accordance with the theory, the data confirmed characteristic differences between the approaches of sensing types and intuitive types, and between the approaches of thinking types and feeling types.

  16. SPME-GC-MS versus Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) analyses for the study of volatile compound generation and oxidation status during dry fermented sausage processing.

    Science.gov (United States)

    Olivares, Alicia; Dryahina, Kseniya; Navarro, José Luis; Smith, David; Spanĕl, Patrik; Flores, Mónica

    2011-03-09

    The use of selected ion flow tube mass spectrometry (SIFT-MS) and gas chromatography-mass spectrometry together with solid phase microextraction (GC-MS-SPME) has been compared in the analysis of volatile compounds during dry fermented sausage processing. Thus, the headspace (HS) of samples of dry fermented sausages with different fat contents was analyzed during their manufacture using both techniques, and significant and positive correlations were found between SIFT-MS and SPME-GC-MS measurements for the compounds pentanal, hexanal, 2-heptenal, octanal, 2-nonenal, 2-butanone, 2-pentanone, ethanol, acetic acid, and hexanoic acid. The oxidative status of fermented sausages during processing was also evaluated, and a significant correlation was obtained between the HS concentration of lipid autoxidation volatile compounds measured by SIFT-MS and SPME-GC-MS and the level of thiobarbituric acid reactive substances (TBARS) in the sausage. The hexanal measured by SIFT-MS resulted in a higher correlation coefficient (r = 0.936) than that obtained using SPME-GC-MS (r = 0.927). SIFT-MS is shown to be a fast, real time analytical technique for monitoring changes in the profile of volatile compounds in dry fermented sausages during processing and a useful tool to evaluate the oxidative status of meat products.

  17. 单向活瓣补片治疗合并重度肺动脉高压双向分流型室间隔缺损%One - way - valved patch for repair of ventricular septal defect with severe pulmonary hypertension with Bi-directional shunt

    Institute of Scientific and Technical Information of China (English)

    邵双印

    2009-01-01

    目的 总结本院自2003年至2008年用自制单向活瓣补片治疗合并重度肺动脉高压双向分流型室间隔缺损15例的经验.方法 对收治的15例合并重度肺动脉高压双向分流的室间隔缺损患者行单向活瓣补片修补室间隔缺损.结果 本组15例病人无手术死亡,疗效满意,1周时有7例右向左分流,3周时右向左分流消失.随访3个月病人自觉症状改善,肺动脉压下降.结论 单向活瓣补片能降低肺动脉高压危象的发生率,降低围术期死亡率,围术期的管理也非常重要.%Objective To summerize the surgical effect with one - way - valved patch to treat vetricular septal de-feet with severe pulmonary hypertension with bi - directional shunt since 2003. Methods The materials of 15 patients with ventricular septal defect and severe PH with bi- directional shunt who were treated by one- way- valved patch were ana-lyzed. Results No patient died in hospital after operation due to pulmonary hypertention crisis and the low output of left ventrical. Most patients felt better than preoperation and their pulmonary artery pressure decreased gradually. Conclusions One -way -valved patch is useful in decreasing the rate of perioparative pulmonary hypertension crisis and perioperation mortality. The perioperative therapy and prioperative evaluation are also essential to raise surgical operation effect.

  18. Pitfalls in the analysis of volatile breath biomarkers: suggested solutions and SIFT-MS quantification of single metabolites.

    Science.gov (United States)

    Smith, David; Spanel, Patrik

    2015-04-01

    The experimental challenges presented by the analysis of trace volatile organic compounds (VOCs) in exhaled breath with the objective of identifying reliable biomarkers are brought into focus. It is stressed that positive identification and accurate quantification of the VOCs are imperative if they are to be considered as discreet biomarkers. Breath sampling procedures are discussed and it is suggested that for accurate quantification on-line real time sampling and analysis is desirable. Whilst recognizing such real time analysis is not always possible and sample collection is often required, objective recognition of the pitfalls involved in this is essential. It is also emphasized that mouth-exhaled breath is always contaminated to some degree by orally generated compounds and so, when possible, analysis of nose-exhaled breath should be performed. Some difficulties in breath analysis are mitigated by the choice of analytical instrumentation used, but no single instrument can provide solutions to all the analytical challenges. Analysis and interpretation of breath analysis data, however acquired, needs to be treated circumspectly. In particular, the excessive use of statistics to treat imperfect mass spectrometry/mobility spectra should be avoided, since it can result in unjustifiable conclusions. It is should be understood that recognition of combinations of VOCs in breath that, for example, apparently describe particular cancer states, will not be taken seriously until they are replicated in other laboratories and clinics. Finally, the inhibiting notion that single biomarkers of infection and disease will not be identified and utilized clinically should be dispelled by the exemplary and widely used single biomarkers NO and H2 and now, as indicated by recent selected ion flow tube mass spectroscopy (SIFT-MS) results, triatomic hydrogen cyanide and perhaps pentane and acetic acid. Hopefully, these discoveries will provide encouragement to research workers to be

  19. Quantification of acetaldehyde and carbon dioxide in the headspace of malignant and non-malignant lung cells in vitro by SIFT-MS.

    Science.gov (United States)

    Sulé-Suso, Josep; Pysanenko, Andriy; Spanel, Patrik; Smith, David

    2009-12-01

    Previous studies using selected ion flow tube mass spectrometry, SIFT-MS, showed that CALU-1 lung cancer cell cultures emit acetaldehyde in proportion to the number of cells in the culture medium. However, studies in another laboratory led to conflicting results, so these SIFT-MS studies have been repeated and extended to include NL20 normal lung epithelial cells and 35FL121 Tel+ telomerase positive lung fibroblast cells. Thus, SIFT-MS has been used to quantify acetaldehyde and, additionally, carbon dioxide, acetone and ethanol in the headspace of the cell culture medium alone and the headspace of the appropriate medium containing 50 x 10(6) or 80 x 10(6) cells following incubation for 16 h at 37 degrees C. Three independent experiments were carried out for each cell type for both cell numbers and for each of the two culture media used. The results showed that acetone and ethanol were only released by the culture medium, specifically from the foetal calf serum contained in the medium, and not by the cells. Acetaldehyde was also released by the medium, but at relatively lower levels than the other three compounds, and was also generated by the CALU-1 and NL20 cell cultures in proportions to the number of cells in the medium. However, following incubation, the acetaldehyde levels in the headspace of the 35FL121 Tel+ cell cultures were much lower than those present in the headspace of the medium alone. Carbon dioxide was clearly generated by the CALU-1 and 35FL121 Tel+ cells indicating that they were respiring normally, but much less was produced by the NL20 cells, presumably indicating that normal metabolism was being inhibited.

  20. Coordinated FA-MS and SIFT-MS analyses of breath following ingestion of D2O and ethanol: total body water, dispersal kinetics and ethanol metabolism.

    Science.gov (United States)

    Spanel, Patrik; Wang, Tianshu; Smith, David

    2005-08-01

    A coordinated study of the dispersal of water between the various body compartments (stomach and gut, blood stream and tissue) and the similar dispersal kinetics of ethanol and its metabolism has been carried out involving two healthy volunteers using flowing afterglow mass spectrometry, FA-MS, and selected ion flow tube mass spectrometry, SIFT-MS. Thus, using these techniques, the variations of HDO and ethanol in breath, measured in successive single exhalations, were followed in real time after the ingestion of measured quantities of D2O and ethanol in proportion to the body weights of the subjects at the dose rates D2O approximately 0.283 g kg-1, ethanol approximately 0.067 g kg-1. During the FA-MS experimental periods (about 2 h), the dispersion of HDO into the body water and finally its equilibration in the total body water is observed from which total body water for each subject was determined. In the SIFT-MS measurements, the dispersion of ethanol into the body water and its loss via metabolism was observed until the physiological (pre-dose) breath level of ethanol for each individual was restored. A simple linear transformation is used to derive the time variations of the blood levels of HDO and ethanol. This has allowed a comparison of the fractions of the ingested ethanol that are metabolized during first-pass metabolism for the two subjects. Thus, in one subject 30% and in the other subject 40% of the ingested alcohol is metabolized in the first 20 min following ingestion. The good time resolution allowed by non-invasive breath analysis ensures that the rates of processes such as ethanol metabolism can be accurately measured. Simultaneous measurements of breath acetaldehyde (largely formed via the ethanol metabolism) and acetone were also performed during the SIFT-MS single breath exhalations.

  1. IMPROVED SIFT IDENTIFICATION ALGORITHM FOR UAV IMAGE BASED ON SIMPLIFIED FORSTNER OPERATOR%基于简化Forstner算子改进的SIFT无人机图像识别算法

    Institute of Scientific and Technical Information of China (English)

    息朝健; 郭三学

    2012-01-01

    This paper addresses the seeking of an identification algorithm for image target fitting UAV features to increase the efficiency of image identification according to the characteristics of UAV that the image information captured is huge and the real-time processing requirement is high. SIFT algorithm has good accuracy and robustness and can overcome some effect of image deformation and occlusion, but it is still hard to achieve real-time processing of UAV images. In the paper we use simplified Foretner operator to improve SIFT algorithm, reduce the computation of feature point recognition process in it. Through the simulation experiment, it proves that the improved SIFT algorithm can raise the accuracy and matching speed of the identification, meet the requirements of UAV in its target identification precision and speed in complicated background.%根据无人机获取图像信息量大、处理实时性要求高的特点,寻找一种符合无人机特点的图像目标识别算法,提高图像识别的效率.SIFT(Scale Invariant Features Transform)算法具有良好的准确性和鲁棒性,能够克服一定的图像形变及遮挡影响,但其还难以满足无人机图像的处理实时性,利用简化的Forstner 算子对SIFT 算法进行改进,降低SIFT算法特征点获取过程的计算量.通过仿真实验,证明改进的SIFT 算法可以提高识别和匹配的速度和准确率,可以满足复杂背景下无人机目标识别精度与速度的需求.

  2. SIFT和SURF在无人机影像匹配的对比研究%Comparative Study of SIFT and SURF in UAV Image Matching

    Institute of Scientific and Technical Information of China (English)

    罗亮; 熊助国

    2016-01-01

    The characteristics of the UAV image, in combination with the characteristics of SIFT and SURF operators, the two operators are com-pared in terms of feature extraction efficiency and feature extraction speed, according to the experiments on two kinds of operators in eval-uating the pros and cons of UAV image matching, the experiments show that SURF has a speed advantage, also in green vegetation cover surface can match is better than SIFT operator.%从无人机影像的特点考虑,结合SIFT和SURF算子的特点进行了两种算子在特征提取有效性、特征提取速度方面的比对,通过对两种算子在无人机影像匹配的实验中凸现的好坏做出评价,实验发现SURF的优势不仅仅在速度上,而且在绿色植被覆盖的地表下能匹配效果要优于SIFT算子。

  3. The use of a portable breath analysis device in monitoring type 1 diabetes patients in a hypoglycaemic clamp: validation with SIFT-MS data.

    Science.gov (United States)

    Walton, C; Patel, M; Pitts, D; Knight, P; Hoashi, S; Evans, M; Turner, C

    2014-09-01

    Monitoring blood glucose concentrations is a necessary but tedious task for people suffering from diabetes. It has been noted that breath in people suffering with diabetes has a different odour and thus it may be possible to use breath analysis to monitor the blood glucose concentration. Here, we evaluate the analysis of breath using a portable device containing a single mixed metal oxide sensor during hypoglycaemic glucose clamps and compare that with the use of SIFT-MS described in previously published work on the same set of patients. Outputs from both devices have been correlated with the concentration of blood glucose in eight volunteers suffering from type 1 diabetes mellitus. The results demonstrate that acetone as measured by SIFT-MS and the sensor output from the breath sensing device both correlate linearly with blood glucose; however, the sensor response and acetone concentrations differ greatly between patients with the same blood glucose. It is therefore unlikely that breath analysis can entirely replace blood glucose testing.

  4. A longitudinal study of ammonia, acetone and propanol in the exhaled breath of 30 subjects using selected ion flow tube mass spectrometry, SIFT-MS.

    Science.gov (United States)

    Turner, Claire; Spanel, Patrik; Smith, David

    2006-04-01

    Selected ion flow tube mass spectrometry, SIFT-MS, has been used to monitor the volatile compounds in the exhaled breath of 30 volunteers (19 males, 11 females) over a 6 month period. Volunteers provided breath samples each week between 8:45 am and 1 pm (before lunch), and the concentrations of several trace compounds were obtained. In this paper the focus is on ammonia, acetone and propanol. It was found that the concentration distributions of these compounds in breath were close to log-normal. The median ammonia level estimated as a geometric mean for all samples was 833 parts per billion (ppb) with a multiplicative standard deviation of 1.62, the values ranging from 248 to 2935 ppb. Breath ammonia clearly increased with increasing age in this volunteer cohort. The geometric mean acetone level for all samples was 477 parts per billion (ppb) with a multiplicative standard deviation of 1.58, the values ranging from 148 to 2744 ppb. The median propanol level for all samples was 18 ppb, the values ranging from 0 to 135 ppb. A weak but significant correlation between breath propanol and acetone levels is apparent in the data. The findings indicate the potential value of SIFT-MS as a non-invasive breath analysis technique for investigating volatile compounds in human health and in the diseased state.

  5. 一种简化的SIFT特征匹配算法研究%Research on the Simplified SIFT Feature Matching Algorithm

    Institute of Scientific and Technical Information of China (English)

    尹丽花; 陈勇; 杨玉平

    2012-01-01

    针对经典SIFT算法因特征描述符维数过高而导致匹配效率降低的问题,本文提出了一种简化的SIFT特征匹配算法,首先对算子进行降维,以提高速度,然后用双向匹配消除错配以保证算法的准确性,实验取得了较好的结果,验证了方法的可行性。%For SIFT algorithm,for the matching problem of the classic descriptors for feature dimension is too high and lead to reduced efficiency,this paper presents a simplified SIFT feature matching algorithm,the first of the operator dimensionality reduction to improve the speed,then use two-way matching to eliminate errors together with the algorithm to ensure the accuracy of experiments and achieved good results,verify the feasibility of the method.

  6. Harris Corner and SIFT Feature of Vehicle and Type Recognition%车辆的Harris与SIFT特征及车型识别

    Institute of Scientific and Technical Information of China (English)

    康维新; 曹宇亭; 盛卓; 李鹏; 姜澎

    2012-01-01

    针对现有车型识别的准确性和实时性不能同时满足要求的问题,提出了复合的图像匹配模型与识别方法.先应用Harris角点对车型初分类,再应用SIFT特征进行细分类,该方法与只利用SIFT特征进行识别的方法相比,在保证识别准确性基本不变的情况下,处理时间减少了近2/3,实时性得到较大改善.%Considering to the important factors of accuracy and real-time performance can not meet the requirement simultaneously in current vehicle recognition,a compound image matching model and a recognition method were developed,namely classifying vehicles firstly by utilizing Harris corner,then classifying vehicles detailedly by using SIFT feature.Compared with the one used SIFT feature only,the method shortens the time of disposal by 2/ 3 under guaranteeing the accuracy to be kept essentially constant,real-time performance was improved greatly.

  7. Mobile selected ion flow tube mass spectrometry (SIFT-MS) devices and their use for pollution exposure monitoring in breath and ambient air-pilot study.

    Science.gov (United States)

    Storer, Malina; Salmond, Jennifer; Dirks, Kim N; Kingham, Simon; Epton, Michael

    2014-09-01

    Studies of health effects of air pollution exposure are limited by inability to accurately determine dose and exposure of air pollution in field trials. We explored the feasibility of using a mobile selected ion flow tube mass spectrometry (SIFT-MS) device, housed in a van, to determine ambient air and breath levels of benzene, xylene and toluene following exercise in areas of high motor vehicle traffic. The breath toluene, xylene and benzene concentration of healthy subjects were measured before and after exercising close to a busy road. The concentration of the volatile organic compounds (VOCs), in ambient air were also analysed in real time. Exercise close to traffic pollution is associated with a two-fold increase in breath VOCs (benzene, xylene and toluene) with levels returning to baseline within 20 min. This effect is not seen when exercising away from traffic pollution sources. Situating the testing device 50 m from the road reduced any confounding due to VOCs in the inspired air prior to the breath testing manoeuvre itself. Real-time field testing for air pollution exposure is possible using a mobile SIFT-MS device. This device is suitable for exploring exposure and dose relationships in a number of large scale field test scenarios.

  8. SAR image multi-scale registration based on FKICA-SIFT features%基于FKICA-SIFT特征的合成孔径图像多尺度配准

    Institute of Scientific and Technical Information of China (English)

    刘向增; 田铮; 史振广; 陈占寿

    2011-01-01

    针对合成孔径(SAR)图像的配准,提出一种基于仿射不变快速核独立成分分析-尺度不变特征变换(FKICA-SIFT)的多尺度配准方法.首先,根据特征点的Hessian矩阵构建仿射不变SIFT描述子.接着,利用FKICA提取该描述子的独立成分得到新的描述子FKICA-SIFT.然后,利用该描述子对Steerable滤波后的各层带通合成子图像提取的特征点进行匹配.最后,采用由粗到细的匹配策略逐步优化变换参数,实现图像的多尺度精确配准.实验结果表明,对有较大仿射变化的SAR图像,当阈值小于0.7时,该方法的匹配正确率大于85%,阈值小于0.5时,匹配正确率可达90%以上,配准精度达到亚像素水平,优于SIFT,PCA-SIFT,ICA-SIFT及SURF等相关方法.使用该方法准确地检测出了地震前后唐家山堰塞湖水域的变化情况,基本满足了SAR图像变换检测前精确配准的要求.%In order to realize automatic registration of a Synthetic Aperture Radar(SAR) image, an approach of image multi-scale registration based on affine invariant Fast Kernel Independent Component Analysis-Scale Invariant Feature Transform(FKICA-SIFT) features is presented. First, the affine invariant SIFT descriptors are constructed according to the Hessian matrix of feature points. The FKI-CA is used to extract the independent components of the affine invariant SIFT descriptors to obtain new descriptors (FKICA-SIFT). After filtering the input images by using Steerable pyramid, the new descriptors are used to match the feature points detected from the synthetic images of the band-pass sub-images in each layer. Finally, a coarse-to-fine procedure is adopted for gradual optimizing transformation parameters to achieve the multi-scale registration results. Experimental results show that the correct matching rate of proposed algorithm is more than 85 % when the threshold is less than 0. 7and that is more than 90% when the threshold is less than 0. 5. The registration

  9. 基于SIFT特征的低区分度点云数据匹配%Low Contrast Point Cloud Data Registration Based on SIFT Feature

    Institute of Scientific and Technical Information of China (English)

    杨红娟; 陈继文; 张运楚; 张君捧; 郝丽丽

    2016-01-01

    Aiming at registration of low contrast point cloud data, which is measured with multi view that changes largely and is accompanied with noise from complex product, a data registration method based on SIFT feature is proposed, which focus on robust feature point identification. Point cloud datax, which reflects the product shape and relationship, is divided into the low frequency part and the high frequency part. Spatial location change has little effect to the low frequency part, while the high frequency part changes greatly with spatial location and product geometric shape characteristics. Gauss homomorphic filter is designed to reduce the low frequency part and increase the high frequency part, improving the contrast of point cloud data. SIFT feature vector of point cloud data is extracted. SIFT feature vector matching is realized with Euclidean distance as the similarity measure to achieve matching points of point cloud data. Quaternion is used to estimate the parameters of point cloud data registration and calculate rotation matrix and translation matrix, achieving low contrast point cloud data regi-stration. Registration example of point cloud data from a brake shell shows the validity of the proposed methods.%针对复杂产品测量视角变化较大、存在测量误差的低区分度点云数据匹配问题,从稳健的特征点识别方法入手,提出基于SIFT特征的低区分度点云数据匹配方法。该方法将反映产品外形及其空间关系的点云数据x表示为受空间位置变化的影响较小的低频部分,以及受到物体自身特性影响较大,随空间位置变化较大的高频部分。设计高斯同态滤波器,在频率域中降低低频分量,增强高频分量,提高点云数据的区分度;然后提取点云数据的 SIFT 特征向量,以欧氏距离作为相似性度量标准进行 SIFT 特征向量的匹配,获得点云数据的匹配点对;最后采用四元数法估计点云数据匹配参

  10. Bi-directional Extensible Converter and Its Distributed Control Strategy for Battery Energy Storage Grid-connected System%用于电池储能系统并网的双向可拓展变流器及其分布式控制策略

    Institute of Scientific and Technical Information of China (English)

    赵彪; 于庆广; 王立雯; 肖宜

    2011-01-01

    With the expansion of the battery energy storage system in size, the traditional centralized converter can no longer satisfy the need of the development of it, and the distributed modular converter become the main development trend. The paper proposed a bi-directional extensible converter and its composition and extention forms for battery energy storage grid-connected system. On this basis, a bi-directional converter principle, which is different from that of the traditional conventer of battery energy storage system, was analyzed. It controls the value and direction of power by changing amplitude and phase-angle difference between two voltage sources with better static and dynamic performances. In order to avoid the shortages of the traditional centralized control method, the distributed control strategy of bi-directional extensible converter was proposed, in which grid-side and battery-side converters were respectively designed to work in passive and active power control. Therefore, the competition of controllers in power regulation was avoided and decoupling control between grid-side and battery-side converters was achieved while converter operating in a unity power factor state. Both simulation and experimental results are consistent with theoretical analyses, and the converter can work properly in both steady and transient processes.%随着储能系统规模的扩大,传统集中式变流器的结构已经无法满足其发展要求,分布式模块化的变流器结构及其控制系统成为发展趋势.提出了一种用于电池储能系统并网的双向可拓展变流器,给出它的2种拆解和拓展形式.在此基础上,分析了双向变流原理,与传统的电池储能变流原理不同,它完全通过控制电压源之间的幅值和相角差来改变功率的大小与流向,具有更好的静动态特性.针对传统集中式的控制方式,提出了双向可拓展变流器的分布式控制策略,将电网侧变流环节设计为被动功率

  11. A Direct Power Control Scheme for Bi-directional Buck/Boost Converters in Motor Drive Systems%电机控制器直流侧前置双向Buck/Boost变换器的直接功率控制策略研究

    Institute of Scientific and Technical Information of China (English)

    张旭辉; 温旭辉; 赵峰

    2012-01-01

    The DC bus voltage fluctuation suppression in the motor drive system with a bi-directional Buck/Boost converter was studied. The disadvantage that the power feed-forward control scheme cannot effectively suppress bus voltage fluctuation was analyzed. A novel direct power control scheme with bus capacitor energy outer control loop and output power inner control loop for the bi-directional Buck/Boost converter was presented. Moreover, in order to improve the dynamic response of converters, a feed-forward term which reflects the changing trends of output power was added on its duty cycle calculation node. The essential difference between the above two control schemes was compared. Results and simulations of the small-signal model analysis and experimental results show the direct power control scheme has good performance in voltage fluctuation suppression.%对电机驱动系统前置双向Buck/Boost变换器后直流母线电压的波动抑制问题进行研究.分析功率前馈控制策略抑制母线电压波动能力较弱的原因.对双向Buck/Boost变换器提出一种母线电容能量外环、输出功率内环的直接功率控制策略,并将输出功率的变化趋势反映到双向Buck/Boost变换器的发波环节,进一步提高了变换器的动态响应特性.基于小信号模型分析上述两种控制策略的本质区别.小信号模型分析结果、仿真和实验结果都证实,提出的直接功率控制策略比功率前馈控制策略有更好的抑制母线电压波动的能力.

  12. The Second Harmonic Current Suppressed by Two Band-Pass Filters and Current Sharing Control Method of Bi-Directional Energy Storage Converters in DC Micro-grid%直流微电网双向储能变换器的两带通滤波器二次纹波电流抑制与均分控制方法

    Institute of Scientific and Technical Information of China (English)

    杨苓; 罗安; 陈燕东; 周乐明; 怀坤山; 伍文华; 陈智勇

    2016-01-01

    含多双向储能变换器的直流微电网通过逆变器接入交流负荷时,会引起直流母线侧产生二次纹波电流,并影响变换器输出电流均分效果。对此,该文提出了双向储能变换器的两带通滤波器二次纹波电流抑制方法,解决了传统电压电流双闭环控制中因限制外环电压的截止频率引起的动态响应速度慢的问题,并增强了二次纹波电流抑制效果。提出了串联微调虚拟电阻的自适应下垂控制方法,减少了储能变换器间输出电压偏差,改善了并联均流效果。在允许的电压偏差范围内,分析了虚拟电阻对输出损失功率和环流的影响,并选取使二者之和达到最小值时合适的控制参数。仿真和实验结果验证了所提方法的有效性。%DC micro-grid with bi-directional energy storage converters accesses AC loads by inverters, generating the second harmonic current in DC bus side, and influences the sharing effect of converters output current. For this reason, the second harmonic current suppressed method by two band-pass filters of the bi-directional energy storage converter was proposed, solving the problem that a very low cut-off frequency of voltage outer loop results in poor dynamic performance in traditional dual loop control strategy, and enhances the suppressed effect of the second harmonic current. An adaptive droop control strategy of series fine tuning virtual resistors was proposed, which can reduce the deviation of energy storage converters output voltage, and improve the sharing effect of parallel converters output current. Within the allowed range of voltage deviation, we analyzed virtual resistors impacting on the output power loss and circulating current, and selected the appropriate control parameters under the condition of the minimum value of both sum. Simulation and experiment results verify the validity of the proposed strategy.

  13. How to Sift Citations.

    Science.gov (United States)

    Parker-Gibson, Necia

    1995-01-01

    To help college teachers assist students in approaching reference materials to obtain citations, basic points that students should identify within citations are specified, and useful classroom techniques and materials are suggested. Common errors in search strategies are also noted. Some suggestions are made for selection of indexes for searching.…

  14. The Big Sift.

    Science.gov (United States)

    McGinty, Tony, Ed.; Reinhold, Fran, Ed.

    1985-01-01

    Presents seven computer coordinators' opinions of 123 microcomputer programs for teaching computer skills, driver education, foreign language, language arts, math, music, problem solving, science, social studies, and typing at preschool, elementary, and secondary levels. Each program listing contains manufacturer information, program description,…

  15. Sift like Eratosthenes

    Science.gov (United States)

    Buczynski, Sandy; Gorsky, Jennifer; McGrath, Lynn; Myers, Perla

    2011-01-01

    The concrete, pictorial, and abstract methods of this lesson give students access to investigate, isolate, define, and use prime numbers. In this article, the authors describe an enrichment lesson that offers opportunities to investigate prime numbers in concrete, pictorial, and abstract ways. Originally introduced by Jerome Bruner in 1960, the…

  16. Improved fully affine invariant SIFT-based image matching algorithm%改进的抗全仿射尺度不变特征变换图像匹配算法

    Institute of Scientific and Technical Information of China (English)

    贺柏根; 朱明

    2011-01-01

    针对现有匹配算法难以解决图像发生仿射变换特别是发生大视角变换时的有效匹配问题,本文对匹配稳定性较好的尺度不变特征变换(SIFT)算法进行了深入研究和改进.借鉴其模拟和归一化相结合的思想对相机光轴的经度角和纬度角进行模拟并采用SIFT算法进行匹配.结果显示,提出的算法不仅保留了SIFT原有的对仿射变换的抵抗能力,而且对视角变换也有很好的鲁棒性,实现了完全的抗仿射变换.实验结果表明,与传统的SIFT算法相比,本文算法对仿射变换尤其是有大视角改变时有更好的适应性.%In image matching process,the affine transformation is difficult to avoid.In exiting algo-rithms,Scale Invarian Feature Transform(SIFT)has strong resistance to changes of scale,rotation,translation and illumination changes generated by affine transformation.However,when an image hasa view angle change,especially large change,the SIFT is not satisfactory.This paper researches theprinciple of the SIFT and improves its matching function.The latitude and longitude of camera axis aresimulated firstly,and then the images are matched by using the improved SIFT algorithm.Experi-ments show that the algorithm not only retains the original advantages of the SIFT algorithm,but al-SO been robust to changes of the angle.It has achieved a complete anti-affine transformation.In con-clusions,the proposed algorithm is more suitable tO affine transformation,especially large angle chan-ges,as compared with SIFT algorithm.

  17. 基于SIFT及射影变换的多摄像机目标交接%Object handoff in multi-cameras based on SIFT and homograph

    Institute of Scientific and Technical Information of China (English)

    杨俊; 战荫伟

    2011-01-01

    To establish the correspondence between moving objects is a key problem in multi-camera surveillance, and field of view (FOV) line is an efficient tool to resolve the consistency in labeling objects.In this paper, we propose an algorithm that realizes object handoff by using scale-invariant features transform (SIFT) and homograph, without knowing the camera calibration information. Firstly, by using SIFT algorithm, matching points are automatically generated between two images sharing a joint region. We chose the matching points which are coplanar in space. These points are then used to compute the homography matrix of the two images. Then, the camera FOV lines are obtained by using the homography matrixand boundary points of the images. Finally, we realize the object handoff using the position of object and homograph. Experimental results show the accuracy and robustness of our method.%运动目标正确交接是多摄像机视频监控中的关键,视野分界线是解决目标交接的有效工具.不需标定摄像机参数,提出了一种利用尺度不变特征变换(SIFT:seale-invariant freatures transform)及射影变换实现目标交接的算法.首先使用SIFT算法在不同视角拍摄的图像间自动生成匹配的特征点,由空间共面的特征点及其相应匹配点生成图像间的单应变换矩阵.然后由图像边界点及单应矩阵计算摄像机视野(FOV:field of view)分界线.最后利用目标位置信息及射影变换实现目标正确交接.实验结果表明本文的方法具有有效性和鲁棒性.

  18. Isoprene levels in the exhaled breath of 200 healthy pupils within the age range 7-18 years studied using SIFT-MS.

    Science.gov (United States)

    Smith, David; Spaněl, Patrik; Enderby, Beth; Lenney, Warren; Turner, Claire; Davies, Simon J

    2010-03-01

    The published results of breath isoprene studies, to date largely involving adults, are briefly reviewed with special attention given to the work done on this topic during the last 10 years using selected ion flow tube mass spectrometry, SIFT-MS. Then the new data recently obtained on isoprene levels in the exhaled breath of some 200 healthy children and young adults (pupils) with ages ranging from 7 to 18 years measured using SIFT-MS are presented in detail. A concentration distribution has been constructed from the data obtained and compared to that for healthy adults also obtained from SIFT-MS data. Although there is overlap between the two distributions, which are close to log normal in both cases, the median level for the young cohort is much lower at 37 parts-per-billion, pbb, geometric standard deviation, GSD, 2.5, compared to that for the adult cohort of 106 ppb with a GSD of 1.65. Further to this, there is a clear increase in the mean breath isoprene concentration with age for the young cohort with a doubling of the level about every 5-6 years until it reaches the age-invariant mean level of that for adult cohort. Should this trend be extrapolated downwards in age it would indicate a near-zero breath isoprene in the newborn that was indicated by a previous study. Indeed, in the present study isoprene was not detected on the breath of two young children. The results reveal mean breath isoprene levels (±SD) for pupils within the given age ranges as 7-10 years (28 ± 24 ppb), 10-13 years (40 ± 21 ppb), 13-16 years (60 ± 41 ppb) and 16-19 years (54 ± 31 ppb). The more rapid increase that occurs between the second and third age ranges is statistically highly significant (p = 0.001) and we attribute this phenomenon to the onset of puberty and the spurt in growth that occurs during this phase of development. There is no significant difference in mean breath isoprene between males and females for both the adult cohort and the younger cohort.

  19. A Fast Method for Aerial Image Registration Based on Improved SIFT%基于改进SIFT的航拍图像快速匹配方法

    Institute of Scientific and Technical Information of China (English)

    石钊铭; 耿伯英; 董银文

    2013-01-01

    Aimming at problems that the calculation of the feature descriptor is complex, the registration time is long and wrong registrations are many in the traditional SIFT algorithm, a fast method for aerial image registration based on improved SIFT is proposed. In the method a improved feature descriptor with 18 dimension consist of 12 gradient values in a circular window, 3 cumulative gray-scale value and 3 gray-scale difference in a concentric circular window. And the initial matched feature point pairs are obtained by the lateral matching method based on correlation coefficient similarity measurement rule. Finally, wrong registrations are removed and affine transformation model is computed by using RANSAC algorithm, and the transformed image is resampled and interpolated by bilinear interpolation. Experiments shows the method is more accurate and take less time than traditional SIFT algorithm in image registration.%针对传统SIFT算法存在特征描述符计算复杂,匹配时间长,错匹配较多等问题,提出了一种基于改进SIFT特征的航拍图像快速匹配方法.该方法采用基于圆形窗口的梯度方向累加值与同心圆形窗口内的灰度累加值、灰度差分值来构建18维的改进特征描述符,并在特征点匹配过程中,采用基于相关系数相似度量准则的双向匹配方法来获取初始匹配特征点对.最后,运用RANSAC算法进一步消除错配和估算仿射变换模型,并通过双线性插值法对变换后的图像进行重采样和插值.实验表明,该方法可以实现航拍图像之间的有效匹配,在匹配速度和匹配精度上优于传统SIFT算法,具有较好的实时性.

  20. SIFT Key-points Self-adaptive Extraction Algorithm for Video Images%视频图像的SIFT特征点自适应提取算法

    Institute of Scientific and Technical Information of China (English)

    余宏生; 金伟其

    2013-01-01

    Before matching the video frames in Scale-Invariant Feature Transform(SIFT)algorithm, the key-points must be extracted firstly. If the size and characteristic of input images are changed, gray threshold of key-points must be reinstalled, to avoid extremely computation cost or failure in registration. In this paper, a self-adaptive SIFT key-points extraction algorithm for video images is developed. The algorithm can set appropriate gray threshold of key-points automatically by feeding parameter of previous frame back to present frame to make the number of key-points extracting from present frame close to the expected value. The experiments show that, when the input image is changed, the key-points number of the video frame always keep near the expected value by setting the threshold self-adaptively. The method makes it possible for digital video images to be registered self-adaptively by SIFT algorithm and the number of feature points remains stable so that the computation costs can be reduced while avoiding registration failure.%采用SIFT算法匹配视频图像帧前,必须首先提取特征点。如果输入图像的大小和特性变化,特征点的灰度阈值必须随之重新设置,以避免过大的计算量和配准失败。提出了一种视频图像的特征点自适应提取算法。该算法能够将前一帧的视频图像的参数反馈到当前帧,自动设置适当的特征点灰度阈值,使得从当前帧提取的关键点的数量接近预期值。实验结果表明,当输入图像改变时,采用自适应设置阈值方法,从视频帧提取的特征点的数量始终保持在预期值。该方法可以通过SIFT算法自适应地配准数字视频图像,使特征点数量保持稳定,避免配准失败,减小计算量。

  1. Disease Prediction in Data Mining Technique – A Survey

    Directory of Open Access Journals (Sweden)

    S. Sudha

    2013-01-01

    Full Text Available Data mining is defined as sifting through very large amounts of data for useful information. Some of the most important and popular data mining techniques are association rules, classification, clustering, prediction and sequential patterns. Data mining techniques are used for variety of applications. In health care industry, data mining plays an important role for predicting diseases. For detecting a disease number of tests should be required from the patient. But using data mining technique the number of test should be reduced. This reduced test plays an important role in time and performance. This technique has an advantages and disadvantages. This research paper analyzes how data mining techniques are used for predicting different types of diseases. This paper reviewed the research papers which mainly concentrated on predicting heart disease, Diabetes and Breast cancer.

  2. Investigation of C3-C10 aldehydes in the exhaled breath of healthy subjects using selected ion flow tube-mass spectrometry (SIFT-MS).

    Science.gov (United States)

    Huang, Juzheng; Kumar, Sacheen; Hanna, George B

    2014-09-01

    Aldehydes have attracted great scientific and clinical interest as potential disease biomarkers. We have investigated selected ion flow tube-mass spectrometry (SIFT-MS) in detecting and quantifying C3 to C10 saturated aldehydes (propanal, butanal, pentanal, hexanal, heptanal, octanal, nonanal and decanal) from the exhaled breath of 26 healthy human volunteers. To assess the reliability of the Nalophan® bag sampling method employed, the water level in the breath sample was measured up to 4 h after collection and showed no significant degradation. Propanal was found to be the most abundant aldehyde in the exhaled breath of healthy volunteers. For the C4-C10 aldehydes, their median concentrations were all less than 3 ppbv, demonstrating only trace quantities are present in the exhaled breath of the 26 healthy volunteers.

  3. 基于颜色直方图的SIFT算法改进%An Improved Method of SIFT Algorithm based on Color Histogram

    Institute of Scientific and Technical Information of China (English)

    李海洋; 文永革

    2013-01-01

    尺度不变特征变换(SIFT)图像匹配算法是基于灰度运算的,对于灰度上相近而在色彩信息上有差别的图像,SIFT算法往往产生误匹配,导致SIFT算法匹配率降低..针对这个问题,结合图像颜色信息,采用颜色直方图方法对SIFT算法进行了改进.实验结果表明,改进算法可以有效区分灰度相近而色彩不同的图像.

  4. Jesus, psychological type and conflict: A study in biblical hermeneutics applying the reader perspective and SIFT approach to Mark 11:11–21

    Directory of Open Access Journals (Sweden)

    Leslie J. Francis

    2016-05-01

    Full Text Available The Marcan account of Jesus riding into Jerusalem on a donkey, cursing the fig tree and overturning the tables of the money changers in the temple provides a classic scriptural reference point for a Christian discussion of conflict. Drawing on psychological type theory and on the reader perspective proposed by the SIFT (sensing, intuition, feeling and thinking approach to biblical hermeneutics and liturgical preaching, this study tests the theory that different psychological types will interpret this classic passage differently. Data collected in two residential programmes concerned with Christianity and conflict from type-aware participants confirmed characteristic differences between the approaches of sensing types and intuitive types and between the approaches of thinking types and feeling types.

  5. Concentrations of some metabolites in the breath of healthy children aged 7-18 years measured using selected ion flow tube mass spectrometry (SIFT-MS).

    Science.gov (United States)

    Enderby, B; Lenney, W; Brady, M; Emmett, C; Spaněl, P; Smith, D

    2009-09-01

    Using selected ion flow tube mass spectrometry (SIFT-MS), measurements have been made of the levels of several metabolites in the exhaled breath of 200 healthy school children. Thus, concentration distributions of each metabolite have been obtained for the first time in the paediatric age range. The median values (in parentheses) of the concentrations in parts per billion, ppb, were ammonia (628), acetone (297), methanol (193), ethanol (187), isoprene (37), propanol (16), acetaldehyde (23) and pentanol (15). Hydrogen cyanide was not present in the breath above the detection limit of 2 ppb in the majority of subjects. The water vapour level (humidity) of the breath samples was routinely measured as a check on the sample integrity. Such data are essential if SIFT-MS breath analyses are to be used as a clinical tool to aid diagnosis and/or as a monitor of disease in children. The levels of metabolites usually followed a log-normal distribution and the levels of some compounds were similar to those obtained previously in adults. Lower values were found in the levels of acetone, ammonia, methanol and isoprene. There were no major variations in relation to gender. Some metabolites showed significant variation in relation to age and body mass index. To our knowledge, these are the first measurements of exhaled mouth breath pentanol levels. The median ammonia levels in mouth-exhaled breath of these children decreased with age, whereas in older adults, ammonia has been shown to increase with age. Breath acetone levels were significantly increased for those who had not eaten for more than 6 h prior to providing the breath sample, although dietary control was not a mandatory aspect of the protocol.

  6. Child: A Learning Model and a Bi-directional Phenomenon.

    Science.gov (United States)

    Shastri, Priyvadan C

    2015-01-01

    Forty-five years of work with children has enriched my knowledge. Child development and psychology has made basic concepts of general psychology and abnormal psychology clearer. 'Meanings' have become more meaningful. It has made me a better professional; large number of communication and teaching skill has been the end result of such a long association with diverse groups of children who needed special care. Apart from professional skills as a clinician and as a teacher, it has made me a better person and a better parent. I have been fortunate to work with a large number and different groups of children who were in some way very special. Some were classified under various disabilities or diagnosed under different categories. I also had the privilege of working with different institutions, e.g., child guidance clinics run by a paediatrics department and a psychiatry department of a general hospital and a teaching hospital. Years of association with College of Special Work and Institute of Social Science have made me understand the very important facet of sociocultural influence on the development of human behaviour. I was further fortunate to work with children in closed and open institutions, residential care units and day care units, institutions where court committed children were observed, treated, trained and cared for, destitute children and delinquent children in remand homes, rescue homes and custodial care homes. I was fortunate to be part of the group which dealt with children who were in conflict with the law, belonging to diverse categories like street children, working children, child sex workers and sexually abused children. This paper is a reflection on experience gained over the decades.

  7. Impact of cloud inhomogeneity on bi-directional reflectance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper uses SHDOM(Spherical Harmonics Discrete Ordinate Method)to calculate the nadir bidirectionaI reflectanee distribution function(BRDF)of the cumulus and stratocumulus fields at the wavelengths of 0.67 μm and 2.13 μm,and discusses the impact of cloud inhomogeneity on BRDF.The cloud fields are adopted from 13RC Phase Ⅱ.which are used to compare 3D radiative transfer models.The simulation results show that the cu field has 6% abnormal BRDF values(BRDF>1)with the increase of solar zenith angle.Further analyses show that grid cells whose BRDF is greater than one gather together at the locaI trough of the top of cloud.These regions can receive not only the direct incident solar beam,but also the beam scattered by the higher cloud of its neighborhood.Hence,the BRDF of those regions is enhanced.The abnormal BRDF phenomenon shows that the cloud inhomogeneity can result in inconsistency between satellite observation and plane parallel theory,implying that the reflectance observed by high resolution satellite is maybe enhanced by the cloud 3D effects.Thus one should take this fact into account when using the product retrieved by these data.The dominant solar zenith angles are quite large in the mid-high altitude area,and the impact of cloud inhomogeneity on these areas may be more significant.

  8. Image Segmentation using bi directional of neural network

    Directory of Open Access Journals (Sweden)

    HimadriNath Moulick

    2016-07-01

    Full Text Available Now a days image processing methods are widely used in medical science, to improve critical disease detection and fast treatment for recovery. Mainly this mechanism detects the disease as soon as possible and also find out the exact point of disorder and calculate the growth of this disease,especially in Squamous cell carcinoma in lower lip. Actinic keratosis which is 1/4 inch in diameter, isa pink or flesh coloured rough spot is one of the most important cause of squamous cell carcinoma,which is mainly grown in sun-exposed area. It is usually grow slowly and affects epidermis layer todermis layer. Our proposed method focuses on five different modules. These methods are including inImage Acquisition module and respective Pre-processing ,Segmentation , Filtering Phase and Edge Detection modules.

  9. Child: A Learning Model and a Bi-directional Phenomenon

    Directory of Open Access Journals (Sweden)

    Priyvadan C Shastri

    2015-01-01

    Full Text Available Forty-five years of work with children has enriched my knowledge. Child development and psychology has made basic concepts of general psychology and abnormal psychology clearer. ′Meanings′ have become more meaningful. It has made me a better professional; large number of communication and teaching skill has been the end result of such a long association with diverse groups of children who needed special care. Apart from professional skills as a clinician and as a teacher, it has made me a better person and a better parent. I have been fortunate to work with a large number and different groups of children who were in some way very special. Some were classified under various disabilities or diagnosed under different categories. I also had the privilege of working with different institutions, e.g., child guidance clinics run by a paediatrics department and a psychiatry department of a general hospital and a teaching hospital. Years of association with College of Special Work and Institute of Social Science have made me understand the very important facet of sociocultural influence on the development of human behaviour. I was further fortunate to work with children in closed and open institutions, residential care units and day care units, institutions where court committed children were observed, treated, trained and cared for, destitute children and delinquent children in remand homes, rescue homes and custodial care homes. I was fortunate to be part of the group which dealt with children who were in conflict with the law, belonging to diverse categories like street children, working children, child sex workers and sexually abused children. This paper is a reflection on experience gained over the decades.

  10. IMAGE CLASSIFICATION ALGORITHM BASED ON PCA-SIFT FEATURES AND BAYESIAN DECISION%基于PCA-SIFT特征与贝叶斯决策的图像分类算法

    Institute of Scientific and Technical Information of China (English)

    涂秋洁; 王晅

    2016-01-01

    In order to cope with the problems that existing SIFT-based image classification algorithms require a large amount of storage space and are sensitive to image backgrounds,this paper presents a novel image classification algorithm which is based on PCA-SIFT features and Bayesian decision.The algorithm first applies the principal component analysis (PCA)to reduce the dimensionality of SIFT from 128 to 36,in training process,it makes regional matching on PCA-SIFT descriptors of the training sample images.In order to improve its robustness on background image interference,we selected the stable PCA-SIFT descriptors in object images based on their matching rates,and then used the maximum likelihood estimation to estimate the probability distribution parameters.Finally we used Bayesian decision theory to implement the image classification.Simulation experiment showed that this algorithm has higher classification accuracy compared with existing SIFT-based image classification methods.It also has minimum storage space requirement and higher computation efficiency.%针对现有的基于SIFT特征的图像分类算法具有较大的储存空间需求及对图像背景较为敏感的问题,提出一种基于PCA-SIFT特征和贝叶斯决策的图像分类算法。该算法首先应用主成分分析将SIFT特征从128维降为36维,在训练过程中,对训练样本图像的PCA-SIFT进行区域匹配。基于匹配率选择目标图像中的稳定PCA-SIFT以提高算法对背景图像干扰的鲁棒性,然后应用最大似然估计估计概率分布参数,最后,应用贝叶斯决策理论实现图像分类。仿真实验表明,该算法与现有的SIFT图像分类算法相比分类精度高,而且具有最小的储存空间需求与较高的计算效率。

  11. 基于SIFT算法的InSAR影像配准方法试验研究%Research on the Co-registration Method of INSAR Based on the SIFT Algorithm

    Institute of Scientific and Technical Information of China (English)

    喻小东; 郭际明; 黄长军; 袁长征

    2013-01-01

    配准是合成孔径雷达干涉测量(InSAR)中极其关键的一个步骤.本文详细介绍了SIFT算法,并根据其特点将其应用于InSAR数据的配准过程中.实验结果表明:SIFT算法在InSAR配准中是一种简单、有效和可靠的配准方法.%Co-registration is an important processing in Synthetic aperture radar interferometry (INSAR). This paper describes the SIFT algorithm,and then applies this method to the registration of INSAR. Experiments show that the co-registration method of SIFT is effective and reliable than the regular method.

  12. A new fast algorithm of self-adaptive search scope for SIFT matching%一种自适应搜索范围的SIFT特征点快速匹配算法

    Institute of Scientific and Technical Information of China (English)

    唐坤; 韩斌

    2014-01-01

    Aiming at the high time cost of feature vectors matching in SIFT, a new fast algorithm, called Auto ARV&DP, of self⁃adaptive search scope for SIFT matching is put forward. Firstly, an appropriate reference vector is computed based on the feature vectors set. Secondly, a self⁃adaptive search scope is determined by this reference vector. Finally, the matching of SIFT is performed in a small feature vectors set, which is filtered by norm. Experi⁃mental results showed that compared with the classical BBF algorithm, Auto ARV&DP can effectively decrease the time cost of feature vector matching of SIFT with no loss of matching performance when the size of feature vector set is large.%针对SIFT特征向量匹配时间成本高的问题,提出了一种自适应搜索范围的快速匹配算法-AutoARV&DP。该算法首先根据特征向量集合计算一个合适的参考向量,然后自适应确定一个搜索范围,最后在一个通过距离过滤后的较小搜索空间中进行特征向量匹配。实验结果表明,与经典的BBF算法相比较,AutoARV&在获得满意匹配效果的同时,能够有效地降低SIFT特征点匹配的时间成本。

  13. Approach of vehicle plate extraction based on HSV color space and SIFT feature%一种基于HSV颜色空间和SIFT特征的车牌提取算法

    Institute of Scientific and Technical Information of China (English)

    杨涛; 张森林

    2011-01-01

    为了克服SIFT算法直接应用在车牌提取中表现出来的执行时间过长、误配率高的缺陷,提出了一种基于HSV颜色空间与SIFT特征的两级车牌提取算法,先使用HSV颜色空间确定车牌的候选区域,进行快速粗定位,再使用SIFT算法对候选区域进行精确定位与倾斜校正,在精确定位的同时也完成了对车牌汉字的辨识.这种方法不仅减少了SIFT特征的计算量,而且也避免了复杂背景对于SIFT特征匹配的干扰,大大提高了匹配准确率.最后通过编程实验证实本算法有良好的性能.%In order to overcome the drawbacks such as slow execution speed and high mismatch rate in directly apply SIFT feature to vehicle plate extraction,this paper proposed a two steps vehicle plate extraction method based on SIFT feature and HSV color space. First roughed location the candidate region use HSV color space in a short time, then adopted SIFT feature to locate the plate precisely and correct the tilt,in the meantime accomplished the recognition task of the Chinese character on the vehicle plate. Through the approach not only reduced the computation of SIFT feature, but also avoided the background interference, so can match the features fast and correct. Experimental results also show that the method has a good performance.

  14. 基于简化SIFT算法的无人机影像重叠度分析%Overlapping degree analysis of images from an unmanned aerial vehicle based on a reduced scale-invariant feature transform (SIFT) algorithm

    Institute of Scientific and Technical Information of China (English)

    邢诚

    2012-01-01

    Compared with traditional images, high-resolution images obtained by unmanned aerial vehicles ( UAV) are superior in many aspects such as low cost, rapidness and convenience. However, the attitude of unmanned aerial vehicles cannot be determined accurately, which leads to a decrease in accuracy and efficiency of automatic matching. There are several ascendant characteristics of a SIFT operator such as invariance to scale, rotation, and lightness, and these characteristics are very useful in increasing the matching accuracy of UAV images; however, the traditional SIFT algorithm is complex and requires a long time for image processing. In this paper, a reduced SIFT method was described and some comparisons were made. The overlap analysis of UAV images were processed based on a reduced SIFT and the random sample consensus ( RANSAC ) algorithm, and the steps of overlap analysis were described. Finally, satisfactory results were obtained.%利用无人机进行低空摄影获取地面高分辨率影像,具有成本低、方便、快捷等优点,但由于无人机飞行姿态不稳定,会导致影像自动匹配效率及准确程度降低.SIFT算子具有良好的尺度、旋转、光照等不变特性,但传统SIFT算法复杂度较高,处理影像时间较长,使数据处理工作效率降低.介绍了一种简化的SIFT算法,并与原SIFT算法做出了对比.说明了影像重叠度分析的主要步骤,将简化的SIFT算法RANSAC算法相结合应用到序列影像重叠度分析中,通过实验证明了可行性.

  15. Unmanned Aerial Vehicle Serial Aerial Image Automatic Registration Based on Improved SIFT Algorithm%改进SIFT算法的小型无人机航拍图像自动配准

    Institute of Scientific and Technical Information of China (English)

    熊自明; 万刚; 闫鹤; 李明

    2012-01-01

    针对小型无人机航拍图像视点离散、视角变化有一定运动规律的特点,首先对航拍图像进行数据预处理,结合Harris特征点和SIFT特征向量的优势,提取Harris特征点、计算特征点的特征半径和SIFT特征向量,并利用PCA降低特征向量的维数;然后采用最邻近(NN)方法进行特征匹配,利用BBF算法搜索特征的最邻近以提高匹配速度;最后采用PROSAC算法提纯特征点匹配对并精确计算运动模型参数,实现了图像的自动配准.实验证明,该图像配准方法在准确性、效率方面较经典的SIFT算法有较大的提高.%Due to the disperse and regular of view points and the view angle of UAV Aerial Image, the image data was preconditioned at first, then the Harris feature points with SIFT feature vectors were combined, Harris feature points were extracted, the characteristics radius of feature points and SIFT feature vector was calculated, and PCA (Principal Component Analysis) was used to reduce the dimension of SIFT feature vectors. And then the most close method (NN) was used to feature matching, the BBF algorithm was applied to search the nearest neighbor feature for improving the matching speed. Finally, the PROSAC algorithm was used to purify initial feature point matching pairs, and motion model parameters were calculated, the image automatic registration was achieved. The results of experiment proved that such algorithm was more efficient and exact than the classic SIFT algorithm.

  16. FA-SIFT study of reactions of protonated water and ethanol clusters with [alpha]-pinene and linalool in view of their selective detection by CIMS

    Science.gov (United States)

    Dhooghe, F.; Amelynck, C.; Rimetz-Planchon, J.; Schoon, N.; Vanhaecke, F.

    2010-02-01

    The use of protonated water clusters and protonated ethanol clusters as reagent ions has been evaluated for the resolution of an interference encountered in CIMS when measuring monoterpenes (C10H16) and linalool (C10H18O) simultaneously. To this end, the reactions of H3O+.(H2O)n (n = 1-3), (C2H5OH)mH+ (m = 1-3) and (C2H5OH.H2O)H+ with [alpha]-pinene and linalool have been characterized in a flowing afterglow-selected ion flow tube (FA-SIFT) instrument at a SIFT He buffer gas pressure of 1.43 hPa and a temperature of 298 K. All reactions with linalool were found to occur at the collision limit. The reaction of (C2H5OH)2H+ with [alpha]-pinene proceeds at half the collision rate and both the reactions of (C2H5OH)3H+ and H3O+.(H2O)3 with [alpha]-pinene have a very low rate constant. All other reactions involving [alpha]-pinene proceed at the collision rate. The reactions of H3O+.H2O, H3O+.(H2O)2, C2H5OH2+, (C2H5OH.H2O)H+ and (C2H5OH)2H+ with [alpha]-pinene mainly proceed by proton transfer. Additionally, ligand switching channels have been observed for the reactions of (C2H5OH)2H+ and H3O+.(H2O)2 with [alpha]-pinene. Protonated linalool was observed as a minor product for the reactions of (C2H5OH.H2O)H+ and H3O+.(H2O)n (n = 1-3) with linalool. For all linalool reactions, a contribution of the dissociative proton transfer product at m/z 137 was found and this ion was the main product ion for the reactions with H3O+.H2O, C2H5OH2+ and (C2H5OH.H2O)H+. For the (C2H5OH.H2O)H+/linalool reaction, ligand switching with both water and ethanol has been observed. Major ligand switching channels were observed for the reactions of (C2H5OH)2H+, (C2H5OH)3H+ and H3O+.(H2O)2 with linalool. Also, for the H3O+.(H2O)3/linalool reaction, several ligand switching channels have been observed. These results are discussed in view of their applicability for the selective detection of monoterpenes and linalool with CIMS instrumentation such as SIFT-MS, PTR-MS and APCI-MS.

  17. The Application of 3D Reconstruction Technology by the Monocular UAV Video Based on VF-SIFT%基于VF-SIFT的单目无人机视频快速三维重建技术应用

    Institute of Scientific and Technical Information of China (English)

    刘睿; 李斌兵; 张月

    2016-01-01

    为完成依托于单目无人机的室外地物三维重建,有效利用尺度不变特征变换匹配算法(Scale-invariant Feature Transform,SIFT)提高重建质量,缩短重建时间,运用多图像平均法平滑噪声,然后运用SIFT算法完成对图像的特征点提取,通过高速SIFT算法(Very FastSIFT,VF-SIFT)为每一个特征点添加4个角度参数,即SIFT扩展描述符,将特征点进行分类匹配,完成了在大地形条件下单个目标的三维重建工作.实验结果表明,该方法减少了三维重建后模型上的孔洞现象,降低了特征点匹配时间,从而在保证重建效果的基础上极大地减少整个三维重建的时间.

  18. 基于Eye Map和SIFT特征的人眼定位%Eye Location Based on Eye Map and SIFT Features

    Institute of Scientific and Technical Information of China (English)

    谢春芝

    2012-01-01

    人脸对齐是人脸识别的前提,精确的人眼定位是人脸对齐的主要手段,为此提出了一种基于eye map和SIFT特征的人眼定位方法.首先根据人眼眼球部分的像素灰度比周围像素灰度更黑的特点,在人脸图像中选出满足该特征的像素点,接着通过排序滤波器得到这些像素点的连续区域及它们的几何中心,然后根据人眼特征点的几何限制粗选出候选的眼球像素点,最后在候选点的特定区域内提取SIFT特征,并采用支持向量机回归的方法得到响应值最大的像素点,该点即为人眼的精确定位点.实验结果分析表明该方法既具有较高的定位精度又具有较快的计算速度.%Eye alignment is the precondition for face registration, and the accurate eye localization is the main method for eye a-lignment. In this paper, a novel eye localization method based on eye map and SIFT feature is presented. First, based on the fact that eyeball is dark and round; those pixels darker than their surroundings are those from a face image. Then, connected regions in the eye map and their geometric centers are obtained by a rank order filter. Once more, candidate suitable eyeball pairs are selected based on a set of geometric constraints. And finally, SIFT features are extracted from the area of candidate eyeball pairs, with which the corresponding values are obtained by the support vector machine regressor. The pixel corresponding to the maximal value is just the accurate eye localization expected. Experiments show that the method not only has higher location accuracy but also has faster computation speed.

  19. SIFT并行结构中的滤波器时分复用控制器%Time division controller for Gaussian filters in SIFT parallel architecture

    Institute of Scientific and Technical Information of China (English)

    张静; 桑红石; 沈绪榜

    2013-01-01

    为了降低尺度不变特征(SIFT)硬件加速的成本,采用时分复用的方式共用一组高斯滤波器来实现高斯差分尺度空间的构造.相应的时分复用控制器通过令牌分配的方式控制各个倍频程(octave)的运行,只有获得相应令牌的倍频程才能使用高斯滤波器组执行操作,并提出了带有优先级的令牌分配算法.采用Altera公司stratixⅡ系列的芯片EP2S60F672C3实现,相比传统的结构,电路的查找表单元数量降低了40%.在125MHz的工作频率下,对于320×240的图像,完成高斯差分尺度空间的构造仅需要0.83 ms.%In order to reduce hardware cost for accelerating SIFT (scale invariant feature transformation) , difference of Gaussian (DoG) scale space was constructed by a set of Gaussian filters in time-division multiplexing way. The time-division multiplexing controller managed data flows of three octaves by assigning tokens. The octave with corresponding token had right to use the Gaussian filters. The algorithm of how to assign tokens with priority was also proposed. The proposed architecture was implemented on an Altera Stratix Ⅱ (EP2S60F672C3). Compared with the conventional architecture, the number of LUTs (look up table) was reduced by 40%. It only took 0. 83 ms to construct DoG scale space for a 320×240 image at 125 MHz.

  20. Panorama Generation of SIFT and Stitch Line Based on CUDA%基于CUDA的SIFT特征与拼接缝的全景图生成

    Institute of Scientific and Technical Information of China (English)

    张凯; 杨红雨; 兰时勇

    2015-01-01

    针对大场景高清全景图的生成需求,提出了一种基于CUDA的SIFT特征与动态规划拼接缝的全景图生成方法。首先进行柱面投影保持各通道视频在重叠区域内成像的视觉一致性,并设计了基于CUDA的SIFT特征提取并行算法和基于RANSAC与特征点的变换模型鲁棒估计算法;然后通过基于HIS色彩空间与梯度空间的动态规划拼接缝实现相邻图像的缝合,并在缝合线两边采用基于三角函数的图像融合算法实现平滑过渡,最终生成高清晰度高分辨率的全景图。结果表明,该方法在满足图像无缝拼接精度的前提下,可消除重叠区域内的重影问题,并大幅度提高拼接速度。%Aiming at the effect of high-definition panorama generation of large scenes,propose a panorama generation method based on dynamic programming seam and SIFT based on CUDA. Firstly,the visual consistency of the overlap regions is guaranteed by the cylindri-cal projection,also design a parallel algorithm of SIFT feature extraction based on CUDA and a robust parameter estimation algorithm based on RANSAC and feature points. Then,the adjacent images are stitched by dynamic programming stitch line based on HIS color space and gradient space. A trigonometric-based image fusion algorithm is used on both sides of the stitch line to realize the smooth tran-sition. The high-definition and high-resolution panorama is finally generated. The proposed method can eliminate the ghosting problem in the overlapping area and significantly improve the stitching speed,on the premise of high-accuracy seamless image mosaic.

  1. 融合SIFT的B样条红外图像非刚性配准%B-spline non-rigid registration algorithm for infrared image based on SIFT

    Institute of Scientific and Technical Information of China (English)

    卢朝梁; 马丽华; 陈豪; 张薇; 于敏; 崔树民

    2014-01-01

    手持式广角镜头红外热像仪所拍摄的不同时刻红外图像具有刚性形变和非刚性形变,传统图像配准算法很难同时矫正刚性形变与非刚性形变,针对该问题,提出一种融合SIFT的B样条配准算法。首先在待配准图像中建立控制网格,其次运用SIFT算法寻找待配准与基准图像间的匹配点对,剔除错误匹配点对并计算出待配准图像与基准图像间的刚性变换参数,接着对控制点进行刚性变换,最后以局部强度和为测度函数,运用B样条非刚性配准算法对广角镜头引起图像的非线性进行矫正。对比实验结果表明,本文算法具有很高配准精度,能够满足实际工程精度要求。%Infrared images obtained by handheld infrared camera with wide-angle lens have rigid and non-rigid deform-ations. Tradition image registration algorithm is difficult to correct the rigid and non-rigid deformations. To solve this problem,B-spline non-rigid registration algorithm based on SIFT is proposed. At first,the control mesh is created in the input image. Then,matching points between input image and template image are found by SIFT algorithm. The rigid transformation parameters are calculated after ignoring the incorrect matching points. Next,the control points are transformed by rigid transformation parameters. Finally,the sum of pattern intensity is used as measurement,and the nonlinear transformation of the image that is caused by wide-angle lens is corrected by B-spline non-rigid registration algorithm. The results of comparison show that the new method has better registration accuracy and it also can meet the requirements of practical engineering accuracy.

  2. 改进SIFT算法在二维图像三维重建中的应用研究%Research on the Application of Improved SIFT Algorithm for 2D Image into 3D Image Reconstruction

    Institute of Scientific and Technical Information of China (English)

    宋人杰; 戚照千

    2014-01-01

    由二维图像恢复到三维立体结构过程中,图像匹配技术是其中很重要的一个环节。由于SIFT算法具有对图像平移、旋转、缩放、甚至仿射变换保持不变性的优点,应用最为广泛。但是SIFT算法也存在一些缺陷,如SIFT匹配点数量有限、重复率高,在大量形状相似区域匹配正确率低,匹配时间长等。本文采用简化SIFT模型进行双向匹配,同时增加了匹配条件即改进欧式距离匹配与余弦匹配相结合,实验结果表明,改进后的SIFT算法缩短了运算时间,提高了匹配的精准度,可以较好的应用于图像匹配中。%In the process of the 2D image restoration into 3D structure, image matching technology is one of important link. Due to image translation, rotation, scaling, and the advantages of affine transformation keep invariance, SIFT algorithm is the most widely used. SIFT algorithm, however, the inherent defects, such as matching SIFT points limited number, high repetition rate and the low accuracy in the shape of a lot of similar area matching, matching time is long, etc. Based on the simplified model of SIFT two-way match [1], at the same time increase the matching conditions improved distance matching combined with cosine matching[2], the experimental results show that the improved SIFT algorithm to shorten the operation time, improves the precision of matching, can be better applied to image matching.

  3. 集成MSER和SIFT特征的遥感影像自动配准算法%Remote Sensing Image Automatic Registration Algorithm of Integrated MSER and SIFT Features

    Institute of Scientific and Technical Information of China (English)

    王晓华; 邓喀中; 杨化超

    2013-01-01

    针对倾斜的遥感影像配准困难问题,提出一种基于集成最大极值稳定区域(MSER)和尺度不变特征转换(SIFT)的互补不变特征的自动影像配准算法。该算法首先应用目前公认的具有最佳仿射不变性的MSER特征区域进行影像的粗匹配,初步校正影像的空间形变。然后在粗匹配基础上采用匹配能力较强的 SIFT 描述子与仿射不变矩描述子相结合,进行精匹配。通过以上两步匹配,可以提高遥感影像配准精度,尤其对倾斜影像效果更明显。最后采用倾斜的无人机(UAV)影像进行试验,并与SIFT配准算法比较。结果表明,本文算法在仿射不变性和匹配正确率方面均优于SIFT配准方法。%An image matching approach which integrates Maximally Stable Extremal Regions (MSER, Maximally Stable Extremal Regions) and Scale Invariant Feature Transformation (SIFT, Scale Invariant Feature Transformation) complementary invariant feature automatically is proposed for the tilt Remote Sensing image registration. Firstly, the images are coarsely matched by applying currently recognized as the best affine invariant MSER features, and the large deformation images are corrected initially. Then the images are fine matched by the matching ability of the SIFT descriptor joint the moments based on the coarse matching. The remote sensing image matching accuracy is improved through the above two steps, especially, the more pronounced effect on the large tilt images. Finally, the UAV(Unmanned Aerial Vehicle) image experiments show that this algorithm is more effective than SIFT algorithm in the affine invariant and matching the correct rate.

  4. Error analisis of passager flow based on the bi-directional flow ratio of the section in crowd gathering early-warning%人群聚集预警中基于断面双向流量比的客流误差分析

    Institute of Scientific and Technical Information of China (English)

    李焘; 金龙哲; 刘建

    2013-01-01

    An early warning method for the risk of crowd gathering based on the bi-directional flow ratio of the section was proposed according to the characteristics of the opposite movement of pedestrian flow at the business street. Its error was analyzed in theory and verified by an example. It is found that using this method as a criterion of crowded events is feasible. Whether the measured values are greater or less than the true values, the error of the ratio between the inward and the outward flow across the section is less than that from a pedestrian flow statistic system, so the method is helpful for improving the accuracy of crowd statistic tools to some extent. In addition, the method can be used as a reference in selecting the type of a pedestrian flow statistic system according to requirements for the measuring accuracy of actual applications.%针对密集人群的安全预警管理,结合商业街人流相向运动的特点,提出通过断面双向流量比进行人群聚集风险预警的思路,并对该方法的误差进行了理论分析和实例验证.结果表明该方法用于商业街聚集人群的风险预警时,不论测量值大于真实值还是测量值小于真实值,经过断面进出比的比值误差均比客流统计系统本身误差更小,从而使客流统计产品在一定范围内精确度有所提高.此外,可应用此方法根据实际要求的测量精度为客流统计设备选型提供依据.

  5. 基于互补PWM控制的双功率变换在混合储能控制中的研究%The Study of the Complex Energy Storage Control of the Bi-Directional Power Transformation Based on the Complementary PWM Control

    Institute of Scientific and Technical Information of China (English)

    李春祥; 李壮举; 王佳; 田乐

    2014-01-01

    暂态过程中出现的电压跌路和负荷冲击会导致母线电压不稳定,从而对微电网运行造成影响。为削弱这一影响,提出基于功率前馈和双闭环控制策略的双功率变换拓扑结构。该结构结合超级电容和蓄电池进行储能,引入Buck/Boost双功率变换回路,对功率半导体器件采用双PWM控制,实现能量双向流动;建立了状态方程模型并对其进行仿真;结果表明,该结构及控制策略能有效抑制暂态过程中直流母线的电压波动,超调量几乎为零,母线电压在400 V处维持恒定。%In order to weaken the influence on micro-grid operation of dc-bus voltage instability caused by Voltage drop or shock load during transient state process,a bi-power conversion topology was presented,which adopted feed-forward and Double-closed-loop control strategy. The program combines the super capacitors and batteries,imports Buck/Boost bi-power conversion circuit,adopts complementary PWM control of the structure of two power semiconductor devices, realizes the energy bi-directional transformation. And the state equation models are built and simulated. The simulation results showed that the voltage fluctuation of the dc-bus voltage is immunized effectively by the structure and the technology,maximum deviation almost is zero and the bus voltage is maintained at 400 V place stationary.

  6. On-line, real time monitoring of exhaled trace gases by SIFT-MS in the perioperative setting: a feasibility study.

    Science.gov (United States)

    Boshier, Piers R; Cushnir, Julia R; Mistry, Vikash; Knaggs, Alison; Španěl, Patrik; Smith, David; Hanna, George B

    2011-08-21

    A study is described of the first on line, real time analyses of the exhaled breath of five anaesthetized patients during the complete perioperative periods of laparoscopic surgery. These breath analyses were achieved using a selected ion flow tube, SIFT-MS, instrument, located in the operating theatre at an acceptable distance from the operating table, and coupled to the endotracheal tube in the ventilation circuit via a 5 metre long capillary tube. Thus, inhalation/exhalation breathing cycles, set to be at a frequency of 10 per minute, were sampled continuously for water vapour, the metabolites acetone and isoprene and the propofol used to induce anaesthesia for each operating period that ranged from 20 min (shortest) to 80 min (longest). Whilst there was some loss of water vapour along the long sampling line, the concentrations of the other trace compounds were not diminished. The breath acetone was essentially at a constant level for each patient, but increased somewhat over the longest operating period due to the onset of lipolysis. Most interesting is the clear increase of breath isoprene following abdomen inflation with carbon dioxide. The vapour of the intravenously injected propofol was detected in the exhaled breath and remained essentially constant during the perioperative period. These analyses were performed totally non-invasively and the data were immediately and constantly available to the anaesthetist and surgeon. Exploitation of this development could influence decision making and potentially improve patient safety within the perioperative setting.

  7. SIFT Feature Extraction Parallel Algorithm on Mobile Device%移动智能终端的SIFT特征检测并行算法

    Institute of Scientific and Technical Information of China (English)

    甘威; 张素文; 雷震; 李怡凡

    2016-01-01

    特征的检测和匹配在计算机视觉应用中是一个重要的组成部分,如图像匹配、物体识别和视频跟踪等.SIFT算法以其尺度不变性和旋转不变性在图像配准领域得到了广泛应用.传统的SIFT算法效率低,因此提出一种在移动智能终端上实现的高效方法.在Android平台利用OpenCL框架实现了移动智能终端的SIFT算法,通过计算任务的重新分配,优化SIFT算法在移动GPU上的并行实现.实验结果表明,移动平台的SIFT算法充分利用了GPU并行计算能力,大大提高了SIFT算法的执行效率,实现了高效的特征检测.

  8. 基于SIFT特征匹配的精准图像配准算法%Algorithm of Image Registration Based on the Precise SIFT Feature Matching

    Institute of Scientific and Technical Information of China (English)

    陈燕文; 徐东平

    2011-01-01

    尺度不变的特征变换方法(SIFT)具有对图像尺度缩放、旋转、放射变换以及亮度变化保存不变的优点,该文提出了一种基于SIFT算法的精准的图像配准方法.首先利用SIFT算法提取图像中的特征点;接着对这些特征点采用相似性准则中的欧式距离进行匹配,得到初始匹配对;由于初始匹配对中存在误匹配对,从而造成匹配的精度不足,因此提出一种改进后的RANSAC(随机取样一致性性算法)消除误匹配对.此外该文通过多次实验,选取SIFT算法中合适的比例阀值,提高配准的精度.实验结果表明,该方法既继承了SIFT算法的鲁棒性,又提高了匹配精度.

  9. 基于SIFT特征降维的视频车辆跟踪研究%Video Vehicle Tracking Based on Dimension Reduction of SIFT Features

    Institute of Scientific and Technical Information of China (English)

    詹智财; 惠浩添; 张松松

    2012-01-01

    针对尺度不变特征变换(SIFT)算法在匹配时特征数量过多导致的耗时过长的问题,该文提出一种基于SIFT和主成分分析(PCA)相结合的SIFT特征降维的视频车辆跟踪算法.首先利用SIFT提取出车辆视频图像帧中的所有特征点及其特征向量,其次使用PCA算法对其维数约减并找出各自的具有代表性的特征参数,达到对特征点向量降维的目的,最后利用欧式距离找出不同车辆图像帧中相似的车辆.实验证明,该算法在保证原SIFT算法鲁棒性、稳定性的同时减少了计算量,增加了匹配效率,增强了实时性.

  10. 一种改进的SIFT特征提取新算法%An improved new algorithm for SIFT feature extraction

    Institute of Scientific and Technical Information of China (English)

    苏丽颖; 李小鹏; 么立双

    2013-01-01

    针对尺度不变特征变换(SIFT)角点提取算法比较复杂、运算速度比较慢的缺点,提出了一种更加快速的SIFT角点提取方法.通过对SIFT算法的分析,提出了一种候选角点筛选与SIFT算法相结合的新算法.首先,应用像素点8邻域相似度方法对要提取角点的图像进行候选角点筛选,然后以候选角点为中心构建3×3的灰度图像,再应用SIFT提取算法对构建的3×3的灰度图像进行角点提取.通过实验和理论推导证明了新算法的有效性.

  11. 月球表面图像的SIFT特征提取与匹配%SIFT Feature Extraction and Matching of Lunar Surface Image

    Institute of Scientific and Technical Information of China (English)

    陈坤; 王璐; 储珺

    2011-01-01

    在分析月球表面不同尺度、不同谱段图像特点的基础上,本文以Visual C++和OpenCV为开发平台,对月球表面多光谱图像数据和多尺度图像对数据进行特征点提取和匹配,并验证算法的有效性.实验结果表明,改进的SIFT特征具有旋转、平移、尺度缩放、亮度变化和视角变换的不变性,能较好地完成月球表面各种图像的特征提取和匹配.%On the basis of analyzing multi-spectral and different-scale lunar surface image feature points, this paper extracts feature point and realizes stereo matching of the multispectral lunar surface image data and multi-scale image pairs data, and verifies the effectiveness of the proposed algorithm with Visual C ++ and OpenCV development platform. Results show that improved SIFT feature is invariant to rotation, scale, intensity roughness, preserves stability of view variations, and completes feature extraction and matching of lunar surface image better.

  12. 基于MMTD的SIFT特征提取算法%Measure of Medium Truth Degree (MMTD)Based SIFT Feature Extraction Algorithm

    Institute of Scientific and Technical Information of China (English)

    杨晓琳; 周宁宁

    2014-01-01

    尺度不变特征变换(SIFT)是一种常用的特征提取算法,但它采用固定的阈值来筛选特征点,匹配效果不是很理想.文中针对SIFT对不同图像无自适应性的缺点,提出了一种新的计算自适应阈值的方法,即将中介真值程度(MMTD)和SIFT相结合,用MMTD改进SIFT算法能够避免为了选取合适的阈值而进行大量的实验.采用MMTD改进阈值来筛选图像中的特征点,再将特征点进行图像匹配.实验结果表明,匹配点的数量比采用传统的SIFT方法增加了约两倍,说明文中所提出的基于MMTD的SIFT特征提取算法是有效的.

  13. Reading and proclaiming the Birth Narratives from Luke and Matthew: A study in empirical theology amongst curates and their training incumbents employing the SIFT method

    Directory of Open Access Journals (Sweden)

    Leslie J. Francis

    2013-07-01

    Full Text Available Drawing on Jungian psychological type theory, the SIFT method of biblical hermeneutics and liturgical preaching suggests that the reading and proclaiming of scripture reflects the psychological type preferences of the reader and preacher. This thesis is examined amongst two samples of curates and training incumbents (N = 23, 27, serving in one Diocese of the Church of England, who completed the Myers-Briggs Type Indicator. Firstly, the narrative of the shepherds from Luke was discussed by groups organised according to scores on the perceiving process. In accordance with the theory, sensing types focused on details in the passage, but could reach no consensus on the larger picture, and intuitive types quickly identified an imaginative, integrative theme, but showed little interest in the details. Secondly, the narrative of the massacre of the infants from Matthew was discussed by groups organised according to scores on the judging process. In accordance with theory, the thinking types identified and analysed the big themes raised by the passage (political power, theodicy, obedience, whilst the feeling types placed much more emphasis on the impact that the passage may have on members of the congregation mourning the death of their child or grandchild.

  14. SIFT-based dense pixel tracking on 0.35 T cine-MR images acquired during image-guided radiation therapy with application to gating optimization

    Energy Technology Data Exchange (ETDEWEB)

    Mazur, Thomas R., E-mail: tmazur@radonc.wustl.edu, E-mail: hli@radonc.wustl.edu; Fischer-Valuck, Benjamin W.; Wang, Yuhe; Yang, Deshan; Mutic, Sasa; Li, H. Harold, E-mail: tmazur@radonc.wustl.edu, E-mail: hli@radonc.wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

    2016-01-15

    Purpose: To first demonstrate the viability of applying an image processing technique for tracking regions on low-contrast cine-MR images acquired during image-guided radiation therapy, and then outline a scheme that uses tracking data for optimizing gating results in a patient-specific manner. Methods: A first-generation MR-IGRT system—treating patients since January 2014—integrates a 0.35 T MR scanner into an annular gantry consisting of three independent Co-60 sources. Obtaining adequate frame rates for capturing relevant patient motion across large fields-of-view currently requires coarse in-plane spatial resolution. This study initially (1) investigate the feasibility of rapidly tracking dense pixel correspondences across single, sagittal plane images (with both moderate signal-to-noise and spatial resolution) using a matching objective for highly descriptive vectors called scale-invariant feature transform (SIFT) descriptors associated to all pixels that describe intensity gradients in local regions around each pixel. To more accurately track features, (2) harmonic analysis was then applied to all pixel trajectories within a region-of-interest across a short training period. In particular, the procedure adjusts the motion of outlying trajectories whose relative spectral power within a frequency bandwidth consistent with respiration (or another form of periodic motion) does not exceed a threshold value that is manually specified following the training period. To evaluate the tracking reliability after applying this correction, conventional metrics—including Dice similarity coefficients (DSCs), mean tracking errors (MTEs), and Hausdorff distances (HD)—were used to compare target segmentations obtained via tracking to manually delineated segmentations. Upon confirming the viability of this descriptor-based procedure for reliably tracking features, the study (3) outlines a scheme for optimizing gating parameters—including relative target position and a

  15. 基于Harris-SIFT的移动机器人视觉定位%Visual Localization for Mobile Robot with Harris-SIFT

    Institute of Scientific and Technical Information of China (English)

    袁亮

    2014-01-01

    目标识别和深度估计是移动机器人视觉定位的两个难点问题.针对这两个问题,文章提出了Harris-SIFT特征提取算法和基于尺度空间的深度估计算法.HarTis-SIFT结合了SIFT(Scale InvariantFeature Transform)算法和Harris角点检测器,去除SIFT得到的不具有显著角点特征的特征点,以提高SIFT特征点集合的整体显著性,从而改善匹配和识别效果.此外,Harris-SIFT只需要为部分SIFT特征点生成特征描述,缩短了计算时间,适合实时应用场合.基于尺度空间的深度估计算法通过计算参考图和目标图的特征尺度比,得到图像中同一目标的近似尺寸比例,再结合参考图中目标的深度信息,便可恢复出目标图中目标的深度信息.实验表明,在移动机器人自主导航过程中,基于Har-ris-SIFT的目标识别体系可以准确而有效地识别目标,同时尺度空间深度估计算法也能较准确地定位目标.结合Harris-SIFT和尺度空间深度估计算法可以很好地完成移动机器人视觉定位.

  16. 基于SIFT特征向量的图像检索优化%Optimization of SIFT-Based Image Retrieval

    Institute of Scientific and Technical Information of China (English)

    肖曼玉; 卢江虎; 谢公南

    2013-01-01

    基于SIFT(scale-invariant feature transform,尺度不变特征转换)向量的图像检索在精度和实时性方面都与使用者的心理预期有较大的偏差,该文在建树(build vocabulary tree)、检索、以及匹配度计算方面做了一些改进,在满足实时性的要求下,提高了检索精度;在建树过程中,重新定义了SIFT特征向量聚类机制,将分类和K均值聚类法结合起来代替传统的K均值聚类法;在进行图像检索时,直接利用已有欧氏距离信息,减少向量之间距离的计算,对SIFT向量统一化处理;最后通过改进单位化处理方法,克服SIFT大数据造成的误差.数值结果表明,改进后vocabulary tree的节点有更强的差异性,克服了将训练集按数量均分而不是按距离均分和直接决定树的层数的缺陷;使得检索时间很好地满足了实时性的要求;改进的单位化方法消除了SIFT大数据的误差,从而极大地提高了检索精度.

  17. 基于改进SIFT算法的视频图像序列自动拼接%Automatic video mosaic imaging based on improved SIFT algorithm

    Institute of Scientific and Technical Information of China (English)

    卢斌; 宋夫华

    2013-01-01

    As the existing methods for video image mosaic take high computational costs and huge computation, this paper proposed a method for making panoramas by getting an adaptive frame and matching method of limiting behavior region. According to inter-frame rate and frame overlap interval of linear model, all frames were matched to their latest neighbor key frames. In the process of mosaic, at the aspect of feature extracting, this paper used the improved SIFT feature operator, and the improved RANSAC algorithm to reduce image registration error. This article used the linear weighting fusion algorithm to achieve the desired gradually-enter gradually-leave effect in the overlap image region. Experiments on video sequences showed that this algorithm could extract mosaic key frames with satisfying quality.%本文提出了一种自适应帧采样和限定特征提取区域的拼接方法,根据帧间重叠率和帧间隔建立线性模型,并把各帧图像对准到其前后的关键帧上.在特征点提取方面,提出了一种改进的SIFT算法进行特征点提取,并采用随机采用一致性(RANSAC)方法来更新匹配点,在图像融合中采用线性加权渐入渐出的自然融合算法.实验结果表明:该方法对一般场景能稳定的抽取到关键帧,并进行拼接,取得了较好的拼接效果.

  18. Fast Hierarchical Registration Method for Remote Sensing Image based on SIFT%一种基于SIFT特征的快速逐层遥感图像配准方法

    Institute of Scientific and Technical Information of China (English)

    侯鹏洋; 季艳; 高峰; 胡蕾

    2014-01-01

    当前SIFT特征分层配准方法中存在特征点匹配复杂度高以及不同时相地物变化导致特征点误匹配等问题,提出一种基于SIFT特征的“低分辨率配准、高分辨率验证”快速逐层遥感图像配准方法.该方法针对同源同分辨率不同时相的遥感图像,通过在金字塔的低分辨率图层匹配特征点对并建立仿射变换模型,在金字塔的高分辨率图层评估并修正模型.实验表明:提出的方法在保证配准精度的前提下,有效提高了配准算法的效率.%For the current automatic image registration based on SIFT,feature point matching algorithm is time-consuming,in addition,the changes of multi-temporal images affect the accuracy of registration,this paper proposes a SIFT-based feature of the "low-resolution matching,high resolution authentication" hierarchical image registration algorithm to improve the above issues.In the proposed algorithm,affine transformation model is established in low-resolution pyramid images and sequentially evaluated and revised by match points in high resolution pyramid images.Experimental results show that the improved SIFT algorithm can reduce the time complexity with rather considerable accuracy.

  19. 基于SIFT和人机交互的遥感影像识别方法研究%Recognition method of remote sensing image based on SIFT algorithm & human-computer interaction

    Institute of Scientific and Technical Information of China (English)

    吕萌

    2011-01-01

    尺度不变特征变换(SIFT)算法具有良好的尺度、光照以及空间旋转不变性,在人机交互的环境中可以很好地识别出影像.介绍了SIFT算法和人机交互原理,并进行了实验论证.实验结果表明,该方法能较好地识别出遥感影像,并具有实时性意义.

  20. Zero-disparity adjustment of multiview stereoscopic images based on SIFT matching%基于SIFT匹配的多视点立体图像零视差调整

    Institute of Scientific and Technical Information of China (English)

    李实秋; 雷建军; 周志远; 张海龙; 范晓红

    2015-01-01

    A zero-disparity adjustment method based on SIFT matching was proposed for multiview stereoscopic images using in autostereoscopic display system. First, SIFT was introduced for pixel matching between adjacent views. Then, the result of SIFT matching was filtered by saliency mask which was extracted using frequency-tuned saliency model, and the key-point of disparity control was selected. Finally, the disparity between the neighboring views was computed based on SIFT matching points, and zero-disparity adjustment was conducted based on the principle of disparity control. The disparity of selected key-point was adjusted to zero. Experimental results demonstrate that the proposed method can effectively adjust the disparity of multiview stereoscopic images and generate vivid and comfortable 3D scenes for autostereoscopic display.%针对多视点自由立体显示系统,提出一种基于SIFT匹配的平行多视点立体图像零视差调整方法。首先,通过SIFT变换提取图像特征关键点、对特征关键点进行匹配,获得精确匹配点。然后,运用频率调和显著性模型计算场景的视觉显著性、提取显著性掩膜,以筛选匹配点作为零视差调整的关键点。最后,依据SIFT匹配点计算视点间视差值,并基于视差调整原理对多视点立体图像进行零视差调整。实验结果表明,所提出的方法适合多视点自由立体显示系统,零视差调整后的多视点立体图像具有良好的自由立体显示效果。

  1. Correlating observed odds ratios from lung cancer case-control studies to SNP functional scores predicted by bioinformatic tools.

    Science.gov (United States)

    Zhu, Yong; Hoffman, Aaron; Wu, Xifeng; Zhang, Heping; Zhang, Yawei; Leaderer, Derek; Zheng, Tongzhang

    2008-03-01

    Bioinformatic tools are widely utilized to predict functional single nucleotide polymorphisms (SNPs) for genotyping in molecular epidemiological studies. However, the extent to which these approaches are mirrored by epidemiological findings has not been fully explored. In this study, we first surveyed SNPs examined in case-control studies of lung cancer, the most extensively studied cancer type. We then computed SNP functional scores using four popular bioinformatics tools: SIFT, PolyPhen, SNPs3D, and PMut, and determined their predictive potential using the odds ratios (ORs) reported. Spearman's correlation coefficient (r) for the association with SNP score from SIFT, PolyPhen, SNPs3D, and PMut, and the summary ORs were r=-0.36 (p=0.007), r=0.25 (p=0.068), r=-0.20 (p=0.205), and r=-0.12 (p=0.370), respectively. By creating a combined score using information from all four tools we were able to achieve a correlation coefficient of r=0.51 (ptools. Our findings suggest that bioinformatic tools are useful in predicting SNP functionality and may facilitate future genetic epidemiological studies.

  2. Object Tracking Algorithm Fusing SIFT and Scale-orientation Adaptive Mean Shift%融合 SIFT和尺度方向自适应的 Mean shift 目标跟踪算法

    Institute of Scientific and Technical Information of China (English)

    文武; 姜涛

    2015-01-01

    由于传统M ean shif t跟踪算法固定了椭圆核的带宽和方向,对尺度和方向变化的目标跟踪定位不准或跟踪丢失。针对这一不足,提出一种尺度方向自适应的目标跟踪算法。首先用SIFT特征跟踪目标,并通过对SIFT特征点尺度和方向的实验分析,发现SIFT特征点的尺度变化和目标的尺度变化成正比、特征点主方向变化角度与目标旋转角度一致,提出目标尺度和方向的计算方法;其次引入相似性变换,利用带方向、可变带宽的椭圆核改进传统 Mean shift跟踪算法,使其能跟踪尺度和方向变化的目标。最后,融合SIFT特征跟踪结果和改进Mean shift的跟踪结果。实验表明:提出的算法能有效地跟踪具有尺度和方向变化的目标,获得的目标尺度、旋转方向参数精度较高,定位也更准确。%For the traditional Mean shift algorithm fixed bandwidth and direction of the ellipse kernel ,so the location of object tracking is inaccurate or lost .For this shortage , this thesis puts forward a kind of scale‐orientation adaptive object tracking algorithm .First of all ,tracked the object with the SIFT features .And then analysis of the SIFT feature’s scale and orientation ,found that the scale change of the SIFT feature point is proportional to that of the object ,the Angle change of the SIFT feature point is the same as that of the object ,puts forward the calculation method of object scale and orientation .Furthermore introduce the similarity transformation ,use variable‐bandwidth and orientation ellipse to improve the traditional Mean shift algorithm ,let it can track the object that scale and orientation changes .Finally ,the algorithm utilizes linear weighted method to fuse the tracking results of SIFT and improved Mean shift ,obtaining the final tracking results .Experiment shows that the proposed algorithm can effectively track the object that the scale and orientation change

  3. Enhanced Predictive Handover for Fast Proxy Mobile IPv6

    Science.gov (United States)

    Jeon, Seil; Kang, Namhi; Kim, Younghan

    Proxy Mobile IPv6 (PMIPv6) has been proposed in order to overcome the limitations of host-based mobility management in IPv6 networks. However, packet losses during doing handover are still a problem. To solve this issue, several schemes have been developed, and can be classified into two approaches: predictive and reactive handover. Both approaches commonly use bi-directional tunnel between mobile access gateways (MAGs). In predictive schemes especially, mobility support for a mobile node (MN) is triggered by simplified link signal strength. Thereafter, the MN sends handover notification to its serving MAG, and is then able to initiate packet forwarding. Therefore, if the MN moves toward an unexpected MAG that does not have any pre-established tunnel with the serving MAG, it may lead to packet losses. In this paper, we define this problem as Early Packet Forwarding (EPF). As a solution, we propose an enhanced PMIPv6 scheme using two-phase tunnel control based on the IEEE 802.21 Media Independent Handover (MIH).

  4. Prediction of Gap Asymmetry in Differential Micro Accelerometers

    Directory of Open Access Journals (Sweden)

    Xiaoping He

    2012-05-01

    Full Text Available Gap asymmetry in differential capacitors is the primary source of the zero bias output of force-balanced micro accelerometers. It is also used to evaluate the applicability of differential structures in MEMS manufacturing. Therefore, determining the asymmetry level has considerable significance for the design of MEMS devices. This paper proposes an experimental-theoretical method for predicting gap asymmetry in differential sensing capacitors of micro accelerometers. The method involves three processes: first, bi-directional measurement, which can sharply reduce the influence of the feedback circuit on bias output, is proposed. Experiments are then carried out on a centrifuge to obtain the input and output data of an accelerometer. Second, the analytical input-output relationship of the accelerometer with gap asymmetry and circuit error is theoretically derived. Finally, the prediction methodology combines the measurement results and analytical derivation to identify the asymmetric error of 30 accelerometers fabricated by DRIE. Results indicate that the level of asymmetry induced by fabrication uncertainty is about ±5 × 10−2, and that the absolute error is about ±0.2 µm under a 4 µm gap.

  5. Sifting through millions of megabits

    CERN Document Server

    2008-01-01

    CERN's Large hadron collider, which came online September 10, is a massive project, both tehcnically and collaboratively. For example, the raw data "coming from the experiment will be about 1 petabyte per second"....

  6. Rejoinder: Sifting through model space

    Science.gov (United States)

    Heisey, Dennis M.; Osnas, Erik E.; Cross, Paul C.; Joly, Damien O.; Langenberg, Julia A.; Miller, Michael W.

    2010-01-01

    Observational data sets generated by complex processes are common in ecology. Traditionally these have been very challenging to analyze because of the limitations of available statistical tools. This seems to be changing, and these are exciting times to be involved with ecological statistics, not just because of the neo-Bayesian revival but also because of the proliferation of computationally intensive methods in general. It is now possible to fit much richer models to observational data than in the relatively recent past, which in turn has stimulated much interest in how to evaluate and compare such models. In such an immature, vibrant, and rapidly growing field, not everyone is going to agree on the best way to do things. This is reflected in the contrast of opinions offered by the discussants. Each offers a thoughtful and thought-provoking critique of our work that reflects the current thinking in a non-negligible segment of the ecological data analysis community. We want to thank them for their insights.

  7. 基于SIFT特征的SAR图像配准方法在玉树地震中的应用%SAR Image Registration Based on SIFT Algorithm and its Application to the 2010 Yushu Earthquake

    Institute of Scientific and Technical Information of China (English)

    贺素歌; 董彦芳; 袁小祥

    2013-01-01

    An improved matching method based on Scale Invariant Features Transform (SIFT) algorithm is proposed in this paper. The Infinite Symmetric Exponential Filter (ISEF) algorithm is adopted to reduce speckle noise before computation of the scale space pyramid. SIFT algorithm is utilized to detect the feature points and skip the first scale-space octave to reduce processing time. And then false matches are deleted in the Euclidean space. Experiments show that the proposed method increases the number of the features and improves the robustness. The match accuracy could meet the requirement of sub-pixel matching and the processing time has been cut by 60%. Finally, earthquake change detection is implemented from ALOS PALSAR images, and the building damage information detected is consistent with the results from high spatial resolution aerial image.%本文针对SAR图像特点,提出了基于改进SIFT(尺度不变特征变换)算法的SAR图像配准方案:①对待配准图像进行ISEF(无限对称指数滤波器)滤波处理,降低图像的斑点噪声;②采用SIFT算法提取特征点,略过差分金字塔第一层的特征点检测,提高时间效率;③在欧氏空间内剔除误匹配点,提高配准精度.实验表明,本文提出的SAR图像配准方案检测到的匹配点对的数量和稳健性都有提高,精度能够满足亚像元级SAR图像的应用需求,且用时比传统SIFT方法减少60%以上.最后对精配准的SAR图像进行震害变化检测,得到的震害分布与高分辨率光学图像上判读的建筑物毁坏情况基本一致.

  8. 一种基于改进SIFT的航拍图像自动配准算法%An automatic aerial image registration algorithm based on SIFT with improved features

    Institute of Scientific and Technical Information of China (English)

    董银文; 苑秉成; 石钊铭; 朱明磊

    2013-01-01

    针对传统SIFT算法匹配时间长、错匹配较多等问题,提出了一种基于改进SIFT特征的航拍图像自动配准算法.首先,通过特征点检测时设定检测极值点数目,按照DOG空间层次结构由粗到精来搜索特征点,并使用改进的SIFT特征描述符生成算法;其次,利用最近邻匹配准则进行初步匹配得到初始匹配点对,并采用双向匹配方法对匹配特征点对进行筛选;然后,基于马氏距离的特征点相似度量方法进行二次匹配,并使用RANSAC算法求取仿射变换模型;最后,通过双线性插值对变换后的图像进行重采样和插值.实验结果表明:该算法可以实现航拍图像之间的有效配准,在配准性能上优于传统SIFT算法.%To solve the problems of long registration time and many wrong registrations in using the traditional scale invariance feature transformation (SIFT) algorithm, an automatic aerial image registration algorithm is proposed based on the SIFT with improved features. Firstly, the feature point was searched according to a coarse-to-fine difference of Gauss (DOG) structure by setting a feature point number threshold, and the improved feature descriptors are used in the algorithm. Then the initial matching feature point pairs were obtained by use of the nearest neighborhood similarity measurement rule, and wrong registrations were removed by the lateral matching method. Mahalanobis distance was used to select right registrations in the second registration, and affine transformation was computed by Random Sample Consensus (RANSAC) algorithm. Finally, the transformed image was resampled and interpolated by means of bilinear interpolation. The experiments results show that the algorithm can achieve more accurate aerial image registration and is better than the traditional SIFT algorithm in performance.

  9. Multi-view Point Clouds Registration and Stitching Based on SIFT Feature%基于SIFT特征的多视点云数据配准和拼接算法

    Institute of Scientific and Technical Information of China (English)

    储珺; 聂春梅; 王璐; 张桂梅

    2011-01-01

    针对无特征标志点的大场景多视点云数据,提出了一种新的基于SIFT特征的配准和拼接算法.算法提出了有效纹理图像的概念,并对有效纹理图像进行SIFT特征提取和匹配;然后将提取的SIFT特征点和匹配关系反射到三维点云数据,获取多视点云数据的特征点和匹配关系,完成多视点云数据的拼接.算法在有效纹理图像中提取和匹配特征点,排除了点云数据中孔洞和无效数据的干扰,并且算法只利用较高鲁棒性的特征点对进行拼接,计算简单,匹配精度和效率都得到提高.对室内和室外两个大场景的2个视点数据进行实验,实验结果证明拼接速度和精度都有较大的提高.%In order to solve multi-view point clouds registration in large non-feature marked scenes, a new registrating and stitching method is proposed based on 2D SIFT (Scale-invariant feature transform) features. First, a texture mapping method is used to generate 2D effective texture image, from which SIFT features can be extracted and matched; then accurate key points and registration relationship between the effective texture images are obtained. The extracted SIFT key pionts and registration relationship are reflected on the 3D point clouds data to obtain key points and registration relationship of multi-view point clouds, so the multi-view point clouds stitching can be completed. In this method, the interference of the hole and ineffective points can be eliminated by using the texture mapping method. Experiments on two-view point clouds in indoor and outdoor scenes are carried out and the results prove that the matching precision and efficiency are greatly improved.

  10. Automatic remote sensing image registration algorithm based on SIFT%基于SIFT的全自动遥感图像配准算法

    Institute of Scientific and Technical Information of China (English)

    余婷; 厉小润

    2013-01-01

    Aiming at the optical image affine transformation of the automatic registration, a coarse-to-fine remote sensing image automatic registration algorithm was proposed. Firstly, the input images were mapped for a local feature vector sets with translation, scaling and rotation invariant characteristic based on SIFT feature. According to the euclidean distance of the feature vector which is taken as the similarity decision measure, the initial matching feature points and the initial model parameter values of the transformation were determined. Secondly, making the mutual information as similarity measure, more established correspondence feature points were obtained based on the position control of the search strategy. Thirdly, the deeply optimized affine transformation model parameters were obtained by using the control points and the weighted least squares optimization algorithm together. In this way, a more sophisticated image registration was completed, and a root mean square error was used to evaluate the result of the registration. Finally joint histogram was taken as the registration precision evaluation standard to test registration effect. Experimental results demonstrate the effectiveness and accuracy of the proposed method.%针对仿射变换的光学图像自动配准精度不高的问题,提出了一种基于特征的由粗到细的遥感图像自动配准算法.首先采用SIFT特征进行了特征点的粗匹配,将输入图像映射为一个具有平移、缩放、旋转不变性的局部特征向量集,采用特征向量的欧氏距离作为相似性判定度量,通过两两比较找出匹配的若干对特征点对作为初始配准点对,以完成输入图像的粗匹配;其次,以互信息作为相似性测度,基于位置控制的搜索策略,确定了更多的特征点的对应关系;然后,利用控制点结合加权最小二乘优化仿射变换的模型参数,完成了图像间的精细配准;最后引入了联合直

  11. Study of video object tracking method in dynamic background based on SIFT%基于SIFT动态背景下的视频目标跟踪方法

    Institute of Scientific and Technical Information of China (English)

    钟露明

    2013-01-01

    提出了一种基于尺度不变性特征变换(SIFT)的视频目标跟踪方法.该方法通过提取前后两帧的SIFT特征,利用全图SIFT特征进行匹配,通过匹配的点对计算两帧的几何变换关系,再利用变换矩阵确定下一帧目标位置,实现了连续状态下的自动跟踪.实验结果表明此方法在遮挡、噪声、旋转、光照、缩放、小视角变化等方面有较好的鲁棒性.

  12. Improved SIFT based on Separated Dimension Searching and Cricoid Feature Descriptor%基于分维搜索和环状描述符的SIFT改进算法

    Institute of Scientific and Technical Information of China (English)

    段富; 张耀宗

    2010-01-01

    针对SIFT算法在极值点搜索和特征计算方面的低效,提出一种基于分维搜索和环状描述符的SIFT匹配算法(SC-SIFT).该算法将SIFT算法中的三维极值点搜索策略分解(separate)为两个维度上的逐维搜索,同时引入了一种新的环状(cricoid)特征描述算子来代替原来高维低效的特征.实验证明,该方法不仅能够提高SIFT算法的执行效率,而且提高匹配正确率,实现了对SIFT算法的优化.

  13. A Fast SIFT Feature Detecting and Matching Method Based on Partitioning Strategy%一种基于分块策略的SIFT特征快速提取与匹配方法

    Institute of Scientific and Technical Information of China (English)

    闸旋; 王慧; 程挺; 李烁; 郭忠磊

    2014-01-01

    通过研究基于GPGPU的SIFT特征匹配,提出一种通过分块处理实现大面阵遥感影像快速匹配的方法。首先采用鲁棒性强的随机采样一致性算法来估计待匹配影像间的单应关系并剔除误匹配点;然后通过单应关系找到待匹配影像间的重叠区域,进而实现大面阵遥感影像的分块SIFT特征提取和匹配。试验证明该算法可较快提取相应航摄测区的同名像点,为后续进行的光束法区域网平差提供了鲁棒的数据源。%After researching SIFT feature detecting and matching based on partitioning strategy, a feature matching method apply to remote sensing imagery of bedding face array by blocking its area is proposed. This method first a-dopt the robust RANSAC algorithm to estimate homography relationship between two images to be matched and e-liminate false matching points, then find overlapping area between two images via the homographic matrix so as to achieve SIFT feature partitioned detecting and matching on remote sensing imagery of bedding face array. The pro-posed algorithm was experimented to verify that it can extract survey area corresponding points quickly, which can be provided as robust data foundation for bundle adjustment next to be conducted.

  14. Application of SIFT Algorithm and Binary Search in the Defect Detection of Product Surface%SIFT算法与折半查找法在产品表面缺陷检测中的应用

    Institute of Scientific and Technical Information of China (English)

    徐青; 韩跃平; 杨志刚

    2014-01-01

    In order to achieve the full range detection of the product structure quality quickly and accurately,first the SIFT algorithm and binary search were selected to find the optimal solution of product which was photographed at any angle in the standard image library.Sec-ondly,according to the prior knowledge turn the product to the angle where the area be identified is and use projection method to segment the region of interest.Finally,images subtract and the calculation of correlation degree is used to determine whether there is defect.The experi-mental result shows that the matching method is used in this paper can save an average of 2.08sthan the traditional fixed-step detection in the premise of ensuring the accuracy of detection.%为了准确快速实现对产品结构质量的全方位完整检测,首先采用 SIFT 算法与折半查找法确定任意角度拍摄的待检产品在标准图像库中最优位置信息,其次根据先验知识将其转到待识别区域所在角度利用投影法分割出感兴趣区域,最后通过减影法及相关度计算判别有无缺陷;实验表明在保证检测准确率的前提下,文章所用匹配方法比传统全周向固定步长方法平均可节省2.08s。

  15. 贵州铜仁产广谱抑菌作用细菌素乳酸菌的筛选及鉴定%On the Sift and Identification of the Broad-spectrum Antibacterial Bacteriocin Produced in Tongren, Guizhou

    Institute of Scientific and Technical Information of China (English)

    胡美忠; 张新卓; 刘芸

    2014-01-01

    从贵州铜仁产发酵食品中分离纯化出70余株乳酸菌,采用Agar-spot-test初筛与排除酸、过氧化氢抑制后复筛出一株能产广谱抑菌作用细菌素的乳酸菌(编号G55),经生理生化及16S rDNA鉴定可知G55为植物乳杆菌。抑菌谱实验表明,G55产生的细菌素能抑制革兰阳性菌及革兰阴性菌的生长;蛋白酶实验表明,G55产生的细菌素对胃蛋白酶、蛋白酶K敏感,对胰蛋白酶、α凝乳蛋白酶部分敏感。%More than 70 strains of lactic acid bacteria are separated and purified from the fermented foods made in Tongren, Guizhou. First, they are preliminarily sifted by means of agar-spot-test and then excluded from the inhibition of the acid and hydrogen peroxide. After a second sift, a strain of lactic acid bacteria named G55 which can produce broad-spectrum antibacterial bacteriocin is chosen from them. After the physiobiochemical experiment and the 16SrDNA identification, it is concluded that G55 is an actobacillus plantarum. According to the antibacterial spectrum experiment, it shows that the bacteriocin produced by G55 can inhibit the growth of both gram-positive bacteria and gram-negative bacteria. Meanwhile, the experiment of protease shows that the bacteriorin is sensitive to pepsin and proteinase K and is partially sensitive to trypsin andαcurd protease.

  16. Modeling, Simulation, and Analysis of a Decoy State Enabled Quantum Key Distribution System

    Science.gov (United States)

    2015-03-26

    perform error reconciliation where quantum communication errors are counted and corrected for using bi-directional error correction algorithms over the...configured to control communications on the quantum channel. QKD systems can be paired with traditional symmetric encryption algorithms (e.g., DES, 3DES, or...Error reconciliation algorithms perform bi-directional error correction of the shared sifted keys to correct for quantum communication errors, while

  17. Automatic Registration of Quad-Rotor UAV Imagery based on SIFT and TPS Algorithm%基于SIFT和TPS算法的四旋翼无人机图像自动配准

    Institute of Scientific and Technical Information of China (English)

    陈本清; 杨燕明; 郑凌虹; 文洪涛

    2013-01-01

    As an important complementarity of remote sensing technique,Unmanned Aerial Vehicle (UAV) is attractive to various applications such as target searching,island management,disaster monitoring and low-altitude photogrammetry.The quad-rotor UAV,Compared to fixed-wing UAV,has the advantages of Vertical-Taking-of-Landing (VTOL) and low-altitude flexible flight.However,the quad-rotor UAV has small-volume and lightweight and is more easily influenced by the wind,the acquired imagery maybe have bigger tile angle and more obvious geometry distortion will would result in more difficulty on the image feature matching and image mosaic.For this question,we apply the Scale Invariant Feature Transformation (SIFT) to image feature matching and Thin Plate Spline (TPS) transformation to automatic registration of the micro quad-rotor UAV imageries in this paper.The registration imagery based on TPS transformation is then compared to that based on the affine transformation and the polynomial transformation by evaluating the visual effect of the mosaic imagery and Root Mean Square (RMS) statistic,which shows that after precise SIFT feature matching,the registration RMS accuracy and the visual effect of mosaic imagery of TPS transformation are best,and satisfies the demand of rapid registration and mosaic of micro quad-rotor UVA imagery,since TPS transformation considered both rigid transformation and partial nonlinear distortion of the micro quad-rotor UAV imagery.%针对四旋翼无人机图像姿态倾角大、图像变形明显等特点,采用尺度不变特征变换(SIFT)算法和薄板样条模型(TPS)对四旋翼无人机图像进行特征点匹配和配准实验研究,从拼接图像的目视效果和配准均方差方面比较分析了TPS模型与常用的仿射变换及多项式变换模型的图像配准效果.结果表明:在SIFT算法精确的同名点匹配下,TPS变换模型能够兼顾四旋翼无人机图像的整体刚性变形及局部的非刚性变形,无论是目

  18. HOTCFGM-2D: A Coupled Higher-Order Theory for Cylindrical Structural Components with Bi-Directionally Components with Bi-Directionally Graded Microstructures

    Science.gov (United States)

    Pindera, Marek-Jerzy; Aboudi, Jacob

    2000-01-01

    The objective of this two-year project was to develop and deliver to the NASA-Glenn Research Center a two-dimensional higher-order theory, and related computer codes, for the analysis and design of cylindrical functionally graded materials/structural components for use in advanced aircraft engines (e.g., combustor linings, rotor disks, heat shields, brisk blades). To satisfy this objective, two-dimensional version of the higher-order theory, HOTCFGM-2D, and four computer codes based on this theory, for the analysis and design of structural components functionally graded in the radial and circumferential directions were developed in the cylindrical coordinate system r-Theta-z. This version of the higher-order theory is a significant generalization of the one-dimensional theory, HOTCFGM-1D, developed during the FY97 for the analysis and design of cylindrical structural components with radially graded microstructures. The generalized theory is applicable to thin multi-phased composite shells/cylinders subjected to steady-state thermomechanical, transient thermal and inertial loading applied uniformly along the axial direction such that the overall deformation is characterized by a constant average axial strain. The reinforcement phases are uniformly distributed in the axial direction, and arbitrarily distributed in the radial and circumferential direction, thereby allowing functional grading of the internal reinforcement in the r-Theta plane. The four computer codes fgmc3dq.cylindrical.f, fgmp3dq.cylindrical.f, fgmgvips3dq.cylindrical.f, and fgmc3dq.cylindrical.transient.f are research-oriented codes for investigating the effect of functionally graded architectures, as well as the properties of the multi-phase reinforcement, in thin shells subjected to thermomechanical and inertial loading, on the internal temperature, stress and (inelastic) strain fields. The reinforcement distribution in the radial and circumferential directions is specified by the user. The thermal and inelastic properties of the individual phases can vary with temperature. The inelastic phases are presently modeled by the power-law creep model generalized to multi-directional loading (within fgmc3dq.cylindrical.f and fgmc3dq.cylindrical.transient.f for steady-state and transient thermal loading, respectively), and incremental plasticity and GVIPS unified viscoplasticity theories (within the steady-state loading versions fgmp3dq.cylindrical.f and fgmgvips3dq.cylindrical.f).

  19. Quasi-dense matching based on color Sift algorithm for 3D reconstruction%一种用于三维重建的彩色Sift准稠密匹配算法

    Institute of Scientific and Technical Information of China (English)

    赵璐璐; 耿国华; 周明全; 王小凤

    2012-01-01

    针对复杂光照条件下Sift算法对彩色图像匹配能力较差,基于Kubelka-Munk理论,提出了一种适用于未标定图像的准稠密立体匹配算法,有助于更精确地进行三维重建.该算法首先求出彩色图像各个像素的颜色不变量,提取彩色特征点并通过构造彩色Sift特征描述子进行初匹配,采用RANSAC鲁棒算法消除误匹配生成种子点;然后依据视差约束提出一种基于视差梯度均值自适应窗口方法,根据视差梯度均值调整搜索范围;最后采用最优先原则进行区域增长.实验证明,该算法能获得比较满意的匹配效果,是一种有效的用于三维重建的准稠密匹配算法.%This paper proposed a quasi-dense matching algorithm based on the Kubelka-Munk theory for uncalibrated images, it contributed to more accurate 3D reconstruction. Because Sift algorithm was less capable of matching for color images under changing illumination. First, it found color invariant of each pixel in color images for extracting color feature points and constructing color sift feature descriptor to match, using RANSAC robust algorithm to eliminate false matches for generating seed points. Then it presented a adaptive window method to adjust search scope, which was based on the mean of disparity gradient according to the parallax constraint. Finally, it used the principle of the highest priority for regional growth. Experiments show that this algorithm can obtain satisfactory quasi-dense matching results, and it is an effective dense matching algorithm for 3D Reconstruction.

  20. Anti-shaking method for impurity detection in oral liquid using simpli-fied SIFT%基于简化SIFT的口服液杂质检测防抖方法

    Institute of Scientific and Technical Information of China (English)

    刘洋; 王耀南; 周雨蓉

    2014-01-01

    In the light inspection machine system for oral liquid impurity detection, due to slight vibration of oral liquid bottle caused by sudden halt of crawler belt used for bottle spinning, in the sequential two pictures of oral liquid bottle cap-tured from high-speed industry camera, pixels sharing the same partial positions cannot be overlapped, which may lead to incorrect result after differential operation of the two pictures. For impurity in oral liquid is very small about micrometer level, mechanical dithering or dirt on the bottle of oral liquid shall pose influence on inspection accuracy because of afore-mentioned reason. This paper will harness SIFT algorithm to register the sequential two pictures. SIFT algorithm is suit-able for high accuracy oral liquid impurity detection system on account of its stability. It improves SITF a little in the aim of adapting to slight vibration range which will generate satisfactory result. In the real process of detection, the algorithm is of high stability and high accuracy.%在口服液灯检机杂质检测系统中,口服液瓶体由于履带搓瓶的急停会有轻微的抖动,造成高速工业摄像机拍摄的前后两帧口服液瓶体图像中位于相同空间位置的像素无法重合在一起,导致前后两帧图像做差分结果出现错误。由于口服液中的杂质很小,一般会达到微米级别,因此机械的扰动以及口服液瓶体上的污点都有可能因位置偏差对检测结果造成影响。采用尺度不变特征检测(SIFT)对系统采集的前后两帧图像进行位置配准。SIFT算法稳定性精度很高,适用于高精度口服液杂质检测系统。基于抖动幅度微弱,对该算法进行了一定的改进与简化,以获得最佳配准结果。在实际检测过程中算法稳定,检测结果准确率很高。

  1. BD-Func: a streamlined algorithm for predicting activation and inhibition of pathways

    Directory of Open Access Journals (Sweden)

    Charles D. Warden

    2013-09-01

    Full Text Available BD-Func (BiDirectional FUNCtional enrichment is an algorithm that calculates functional enrichment by comparing lists of pre-defined genes that are known to be activated versus inhibited in a pathway or by a regulatory molecule. This paper shows that BD-Func can correctly predict cell line alternations and patient characteristics with accuracy comparable to popular algorithms, with a significantly faster run-time. BD-Func can compare scores for individual samples across multiple groups as well as provide predictive statistics and receiver operating characteristic (ROC plots to quantify the accuracy of the signature associated with a binary phenotypic variable. BD-Func facilitates collaboration and reproducibility by encouraging users to share novel molecular signatures in the BD-Func discussion group, which is where the novel progesterone receptor and LBH589 signatures from this paper can be found. The novel LBH589 signature presented in this paper also serves as a case study showing how a custom signature using cell line data can accurately predict activity in vivo. This software is available to download at https://sourceforge.net/projects/bdfunc/.

  2. Predicting future of predictive analysis

    OpenAIRE

    Piyush, Duggal

    2014-01-01

    With enormous growth in analytical data and insight about advantage of managing future brings Predictive Analysis in picture. It really has potential to be called one of efficient and competitive technologies that give an edge to business operations. The possibility to predict future market conditions and to know customers’ needs and behavior in advance is the area of interest of every organization. Other areas of interest may be maintenance prediction where we tend to predict when and where ...

  3. 嵌埋于沸石分子筛中的Fen团簇的磁性能研究%Study on magnetic properties of Fen clusters embebed in zeolite molecule-sift

    Institute of Scientific and Technical Information of China (English)

    张万里; 张文旭; 蒋洪川; 彭斌; 杨仕清

    2001-01-01

    The exchange interaction among metal spherical clusters had been discussed by means of RKKY theory. And the relation effect between the magnetic properties of Fen clusters systems embeded in zeolite molecule-sift and the clusters dimension had been investigated by Monte Carlo simulation. It was shown that the magnetic properties of embeded clusters system oscillated with the distance between clusters, and its magnetization increased with the increasing of clusters density and fill efficiency. The results provided a guide for preparing new magnetic composite materials.%运用RKKY理论,推导了金属球形团簇间交换作用,并利用蒙特卡罗(MC)方法模拟了嵌埋于沸石分子筛中的Fen团簇体系的磁性能与团簇尺寸的关联效应。结果表明:嵌埋式团簇体系的磁性能随团簇间距离呈震荡型,体系磁化强度随团簇分布密度及填充率的增大而增大,这对新型复合磁性材料的制备提供了参考。

  4. 基于SIFT特征及改进Gabor滤波器的低质量指纹增强算法%Enhancement Algorithm Based on SIFT Features and the Improvement of Gabor Filter Low-quality Fingerprint

    Institute of Scientific and Technical Information of China (English)

    张升斌; 李吉成; 陈小波

    2013-01-01

    Parameter values for the ridge orientation Gabor filtering process are not precise enough. Based on the frequency parameters of the ridge strike and the inefficient method shortcomings, this paper suggests improvements for the actual needs of the incomplete site low-quality fingerprint process, before the Gabor filter to increase the SIFT analysis method of noise suppression to some extent to improve the Gabor filter accuracy, thus obtaining the effective low-quality filtering of incomplete fingerprint enhancement. In this paper, the feasibility and applicability of the algorithm are verified by a series of theoretical analysis and experiments.%针对指纹增强Gabor滤波过程中指纹纹线方向参数取值不够精确、指纹纹线频率参数求取方法效率不高的缺点,对现场低质量残缺指纹处理过程中的实际需求提出改进,在Gabor滤波器前增加SIFT分析,通过在某种程度上抑制噪声来提高Gabor滤波精度,从而有效地实现对低质量残缺指纹的滤波增强.通过一系列理论分析和实验验证了算法的可行性和适用性.

  5. A SIFT ion-molecule study of some reactions in Titan's atmosphere. reactions of N(+), N(2)(+), and HCN(+) with CH(4), C(2)H(2), and C(2)H(4)

    Science.gov (United States)

    Anicich, Vincent G.; Wilson, Paul; McEwan, Murray J.

    2004-01-01

    The results of a study of the ion-molecule reactions of N(+), N(2)(+), and HCN(+) with methane, acetylene, and ethylene are reported. These studies were performed using the FA-SIFT at the University of Canterbury. The reactions studied here are important to understanding the ion chemistry in Titan's atmosphere. N(+) and N(2)(+) are the primary ions formed by photo-ionization and electron impact in Titan's ionosphere and drive Titan's ion chemistry. It is therefore very important to know how these ions react with the principal trace neutral species in Titan's atmosphere: Methane, acetylene, and ethylene. While these reactions have been studied before the product channels have been difficult to define as several potential isobaric products make a definitive answer difficult. Mass overlap causes difficulties in making unambiguous species assignments in these systems. Two discriminators have been used in this study to resolve the mass overlap problem. They are deuterium labeling and also the differences in reactivities of each isobar with various neutral reactants. Several differences have been found from the products in previous work. The HCN(+) ion is important in both Titan's atmosphere and in the laboratory.

  6. Predictive medicine

    NARCIS (Netherlands)

    Boenink, Marianne; Have, ten Henk

    2015-01-01

    In the last part of the twentieth century, predictive medicine has gained currency as an important ideal in biomedical research and health care. Research in the genetic and molecular basis of disease suggested that the insights gained might be used to develop tests that predict the future health sta

  7. An Operating Method Using Prediction of Photovoltaic Power for a Photovoltaic-Diesel Hybrid Power Generation System

    Science.gov (United States)

    Yamamoto, Shigehiro; Sumi, Kazuyoshi; Nishikawa, Eiichi; Hashimoto, Takeshi

    This paper describes a novel operating method using prediction of photovoltaic (PV) power for a photovoltaic-diesel hybrid power generation system. The system is composed of a PV array, a storage battery, a bi-directional inverter and a diesel engine generator (DG). The proposed method enables the system to save fuel consumption by using PV energy effectively, reducing charge and discharge energy of the storage battery, and avoiding low-load operation of the DG. The PV power is simply predicted from a theoretical equation of solar radiation and the observed PV energy for a constant time before the prediction. The amount of fuel consumption of the proposed method is compared with that of other methods by a simulation based on measurement data of the PV power at an actual PV generation system for one year. The simulation results indicate that the amount of fuel consumption of the proposed method is smaller than that of any other methods, and is close to that of the ideal operation of the DG.

  8. Low torque hydrodynamic lip geometry for bi-directional rotation seals

    Science.gov (United States)

    Dietle, Lannie L.; Schroeder, John E.

    2009-07-21

    A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.

  9. A Bi-directional Energy Splitable Model for Energy Optimization in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    A. Rajeswari

    2011-01-01

    Full Text Available Wireless Sensor Networks is a budding  prototype of networking and computing, where a node may be self powered and individual node have the capability to sense and compute and communicate. Wireless Sensor Networks have been proposed for variety of applications such as Industrial control and monitoring and home automation and consumer electronics and security andMilitary sensing, Asset tracking and supply chain management, Intelligent Agriculture, Missile directing, Fire alarming, Landslide Warning, Environmental monitoring and health monitoring and commercial applications. In Wireless Sensor Network large number of nodes are deployed randomly. Depends on the network architecture the application may be personalized such as Energy Efficiency, Routing and Power Management and data dissemination. Energy Optimization involves in minimizing an energy expenditure and maximizing the lifetime of the complete network. In the proposed work, the placement of nodes are directly involved with residual energy. Energy Optimization in sensor network is very difficult task to achieve it. The optimization of energy is performed through Bidirectional Energy Splitable Model. The data flow in both forward and backward directions are considered, In order to achieve the best QOS in transmission, some parameters such as load, delay and direction of individual nodes are considered. A mathematical model is developed to determine the data flow of  individual node based on the residual energy.

  10. Direct modulation of GFAP-expressing glia in the arcuate nucleus bi-directionally regulates feeding

    Science.gov (United States)

    Chen, Naiyan; Barak, Boaz; Sur, Mriganka

    2016-01-01

    Multiple hypothalamic neuronal populations that regulate energy balance have been identified. Although hypothalamic glia exist in abundance and form intimate structural connections with neurons, their roles in energy homeostasis are less known. Here we show that selective Ca2+ activation of glia in the mouse arcuate nucleus (ARC) reversibly induces increased food intake while disruption of Ca2+ signaling pathway in ARC glia reduces food intake. The specific activation of ARC glia enhances the activity of agouti-related protein/neuropeptide Y (AgRP/NPY)-expressing neurons but induces no net response in pro-opiomelanocortin (POMC)-expressing neurons. ARC glial activation non-specifically depolarizes both AgRP/NPY and POMC neurons but a strong inhibitory input to POMC neurons balances the excitation. When AgRP/NPY neurons are inactivated, ARC glial activation fails to evoke any significant changes in food intake. Collectively, these results reveal an important role of ARC glia in the regulation of energy homeostasis through its interaction with distinct neuronal subtype-specific pathways. DOI: http://dx.doi.org/10.7554/eLife.18716.001 PMID:27751234

  11. Digital interface for bi-directional communication between a computer and a peripheral device

    Science.gov (United States)

    Bond, H. H., Jr. (Inventor); Franklin, C. R.

    1984-01-01

    For transmission of data from the computer to the peripheral, the computer initially clears a flipflop which provides a select signal to a multiplexer. A data available signal or data strobe signal is produced while tht data is being provided to the interface. Setting of the flipflop causes a gate to provide to the peripherial a signal indicating that the interface has data available for transmission. The peripheral provides an acknowledge or strobe signal to transfer the data to the peripheral. For transmission of data from the peripheral to the computer, the computer presents the initially cleared flipflop. A data request signal from the peripheral indicates that the peripheral has data available for transmission to the computer. An acknowledge signal indicates that the interface is ready to receive data from the peripheral and to strobe that data into the interface.

  12. Inductorless bi-directional piezoelectric transformerbased converters: Design and control considerations

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh

    in one package. Moreover, a progress of increasing power capability of piezoelectric transformer’s was a step forward to overcome the limitations in the technology of the piezoelectric transformers. Operation of unidirectional topology deals with finding solutions for advance control of piezoelectric......, this brings an open area for conducting further research which has been subject of this project. The research on this type of power converters are progressive but still very new in the technology to become a successful commercial product. The unique characteristics of piezoelectric transformers i.e. low...... electromagnetic interference, compact, light, high power density and low cost allows for promising market in the near future. The piezoelectric transformer technology has the potential to be used in various applications e.g. motor driver for magnetic resonance imaging scans, the electronic ballast for fluorescent...

  13. Interactive Furniture: Bi-directional Interaction with a Vibrotactile Wearable Sensate Vest in an Urban Space

    DEFF Research Database (Denmark)

    Morrison, Ann Judith; Leegaard, Jack Højholt; Manresa, Cristina

    2017-01-01

    In this study we investigate the experience for participants while wearing a vi-brotactile vest that interacts with a vibroacoustic architecture The Humming Wall, set in an urban space. This public large scale artefact is built to exchange vibrotactile and physiological interactions with a vibrot...

  14. Numerical modelling of chirality-induced bi-directional swimming of artificial flagella

    NARCIS (Netherlands)

    Namdeo, S.; Khaderi, S. N.; Onck, P. R.

    2014-01-01

    Biomimetic micro-swimmers can be used for various medical applications, such as targeted drug delivery and micro-object (e. g. biological cells) manipulation, in lab-on-a-chip devices. Bacteria swim using a bundle of flagella (flexible hair-like structures) that form a rotating cork-screw of chiral

  15. Optimization of Bi-Directional Flyback Converter for a High Voltage Capacitor Charging Application

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Schneider, Henrik; Zhang, Zhe;

    2014-01-01

    This paper presents an optimization technique for a flyback converter with a bidirectional energy transfer. The main goal is to optimize the converter for driving an incremental dielectric electro active polymer actuator, which must be charged and discharged from 0 V to 2500 V DC, supplied from a...

  16. Soft-In Soft-Out DFE and Bi-directional DFE

    CERN Document Server

    Jeong, Seongwook

    2011-01-01

    We design a soft-in soft-out (SISO) decision feedback equalizer (DFE) that performs better than its linear counterpart in turbo equalizer (TE) setting. Unlike previously developed SISO-DFEs, the present DFE scheme relies on extrinsic information formulation that directly takes into account the error propagation effect. With this new approach, both error rate simulation and the extrinsic information transfer (EXIT) chart analysis indicate that the proposed SISO-DFE is superior to the well-known SISO linear equalizer (LE). This result is in contrast with the general understanding today that the error propagation effect of the DFE degrades the overall TE performance below that of the TE based on a LE. We also describe a new extrinsic information combining strategy involving the outputs of two DFEs running in opposite directions, that explores error correlation between the two sets of DFE outputs. When this method is combined with the new DFE extrinsic information formulation, the resulting "bidirectional" turbo-...

  17. High Efficiency Interleaved Bi-Directional ZVS DC-DC Converter

    DEFF Research Database (Denmark)

    Zafar Ullah Khan, M.; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar

    2013-01-01

    MOS drain-to-source voltage always falls to zero before it turns on and ZVS is achieved. Multiphase interleaved inductors are used to achieve high power and low ripple currents. Converter is operated at 50kHz and MATLAB Simulink simulation is performed. 6kW prototype converter is implemented in buck mode...

  18. Rad-hard Reconfigurable Bi-Directional Level Shifters Technology for Micro- and Nanosatellites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Various technologies available to space system designers that operate at different voltage levels. It is, however, important to interface, maintain, and update these...

  19. Crowdsourced bi-directional disaster reporting and alerting on smartphones in Lao PDR

    OpenAIRE

    Frommberger, Lutz; Schmid, Falko

    2013-01-01

    Natural disasters are a large threat for people especially in developing countries such as Laos. ICT-based disaster management systems aim at supporting disaster warning and response efforts. However, the ability to directly communicate in both directions between local and administrative level is often not supported, and a tight integration into administrative workflows is missing. In this paper, we present the smartphone-based disaster and reporting system Mobile4D. It allows for bi-directio...

  20. Dosimetric characterization of a bi-directional micromultileaf collimator for stereotactic applications.

    Science.gov (United States)

    Bucciolini, M; Russo, S; Banci Buonamici, F; Pini, S; Silli, P

    2002-07-01

    A 6 MV photon beam from Linac SL75-5 has been collimated with a new micromultileaf device that is able to shape the field in the two orthogonal directions with four banks of leaves. This is the first clinical installation of the collimator and in this paper the dosimetric characterization of the system is reported. The dosimetric parameters required by the treatment planning system used for the dose calculation in the patient are: tissue maximum ratios, output factors, transmission and leakage of the leaves, penumbra values. Ionization chambers, silicon diode, radiographic films, and LiF thermoluminescent dosimeters have been employed for measurements of absolute dose and beam dosimetric data. Measurements with different dosimeters supply results in reasonable agreement among them and consistent with data available in literature for other models of micromultileaf collimator; that permits the use of the measured parameters for clinical applications. The discrepancies between results obtained with the different detectors (around 2%) for the analyzed parameters can be considered an indication of the accuracy that can be reached by current stereotactic dosimetry.