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Variation in target volume and centroid position due to breath holding during four-dimensional computed tomography scanning: A phantom study

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JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS 2020年第1期21卷 11-17页

作者： Miyamae, Yuta Akimoto, Mami Sasaki, Makoto Fujimoto, Takahiro Yano, Shinsuke Nakamura, Mitsuhiro Kyoto Univ Hosp Div Clin Radiol Serv Kyoto Japan Natl Canc Ctr Dept Radiol Technol Radiol Diag Tokyo Japan Kurashiki Cent Hosp Dept Radiat Oncol Okayama Japan Kyoto Univ Grad Sch Med Div Med Phys Dept Informat Technol & Med EngnHuman Hlth Sci Kyoto Japan

This study investigated the effects of respiratory motion, including unwanted breath holding, on the target volume and centroid position on four-dimensional computed tomography (4DCT) imaging. Cine 4DCT images were reconstructed based on a time-based sorting algorithm, and helical 4DCT images were reconstructed based on both the time-based sorting algorithm and an amplitude-based sorting algorithm. A spherical object 20 mm in diameter was moved according to several simulated respiratory motions, with a motion period of 4.0 s and maximum amplitude of 5 mm. The object was extracted automatically, and the target volume and centroid position in the craniocaudal direction were measured using a treatment planning system. When the respiratory motion included unwanted breath-holding times shorter than the breathing cycle, the root mean square errors (RSME) between the reference and imaged target volumes were 18.8%, 14.0%, and 5.5% in time-based images in cine mode, time-based images in helical mode, and amplitude-based images in helical mode, respectively. In helical mode, the RSME between the reference and imaged centroid position was reduced from 1.42 to 0.50 mm by changing the reconstruction method from time- to amplitude-based sorting. When the respiratory motion included unwanted breath-holding times equal to the breathing cycle, the RSME between the reference and imaged target volumes were 19.1%, 24.3%, and 15.6% in time-based images in cine mode, time-based images in helical mode, and amplitude-based images in helical mode, respectively. In helical mode, the RSME between the reference and imaged centroid position was reduced from 1.61 to 0.83 mm by changing the reconstruction method from time- to amplitude-based sorting. With respiratory motion including breath holding of shorter duration than the breathing cycle, the accuracies of the target volume and centroid position were improved by amplitude-based sorting, particularly in helical 4DCT.

关键词： 4DCT breath-holding time scan mode sorting algorithm

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Integrating LiDAR and high-resolution imagery for object-based mapping of forest habitats in a heterogeneous temperate forest landscape

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INTERNATIONAL JOURNAL OF REMOTE SENSING 2018年第23期39卷 8859-8884页

作者： Gonzalez, Ramiro Silveyra Latifi, Hooman Weinacker, Holger Dees, Matthias Koch, Barbara Heurich, Marco Univ Freiburg Dept Biometry & Environm Syst Anal Tennenbacherstr 4 D-79106 Freiburg Germany KN Toosi Univ Technol Fac Geodesy & Geomat Engn Tehran Iran Univ Wurzburg Dept Remote Sensing Wurzburg Germany Univ Freiburg Chair Remote Sensing & Landscape Informat Syst Freiburg Germany Univ Freiburg Chair Wildlife Ecol & Management Freiburg Germany

Land-cover mapping (LCM) at a fine scale would be useful for forest management across heterogeneous natural landscapes. However, the heterogeneity of land covers at such scales results in complex spectral and textural properties that hinder the applicability of LCM. Besides, the method suffers from, e.g. inconsistent representation of different land-cover types, lack of sufficient and balanced training samples, and instability of classifiers trained by a high number of predictor variables. Even well-known object-based classification approaches are challenged with an objective evaluation of segmentation outputs. Here we classified partially ambiguous land-cover types across heterogeneous forest landscapes in the Bavarian Forest National Park (Germany) by combining metrics from airborne light detection and ranging (LiDAR) and colour infrared (CIR) imagery data and a random forest classifier implemented in an object-based paradigm. We evaluated the segmentation results by creating a global quality score based on inter- and intra-measurements of variance and the number of segments. Selected segmentation outputs were combined with balanced training samples to run the classification algorithm based on representative blocks within the national park. The entire processing chain was implemented in an open-source domain. The final segmentation consisted of LiDAR-based height, image-based Normalized Difference Vegetation Index (NDVI) and red band, with 20 cluster seeds and a minimum segment size of 40 pixels. In the classification, the most important variables included the height of the top layer, NDVI, Enhanced Vegetation Index (EVI) and Green-Red Vegetation Index (GRVI). The average values of 500 random forest runs indicated an overall accuracy of 86.6% and an estimated Cohen's kappa coefficient of 85.2%, with different probabilities of correct classification for land-cover classes. Mature deciduous, standing deadwood, fallen deadwood, meadow, and bare soil classes were clas

关键词： Classifiers object orientation temperate forest sorting algorithm normalized difference vegetation index Taxonomy Bavarian Forest forest habitats Lidar Heterogeneous Disease Predictive Factor Lowest common multiple High resolution imaging

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USING APPLIANCE SIGNATURES FOR MONITORING RESIDENTIAL LOADS AT METER PANEL LEVEL

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IEEE TRANSACTIONS ON POWER DELIVERY 1991年第4期6卷 1380-1385页

作者： SULTANEM, F Direction des Etudes et Recherches Electricitd de France Clamart France

As an initial approach, in order to identify electrical household appliances strictly by analyzing variations in current-voltage signals at meter panel level may seem to be utopian or, to say the least, an ambitious undertaking. However, on observation of the currents consumed by these appliances it is surprising to see that each one of them is recognizable and perfectly identifiable by a certain number of parameters. Nevertheless, difficulties flow from the fact that an appliance is generally switched on while other appliances are already in use. The main issue is then to isolate the characteristic parameters of the appliance from the aggregate signal. One is also aware that the success of the identification does not only depend on the efficiency of the monitoring device, but also on a set of circumstances relating to the composition of the range of appliances installed on the measurement site, and the random sequencing of their operation. This paper presents a study whose aim is to show the feasibility of this device. In particular, it presents the test findings secured on site using a test prototype.

关键词： site measurements sorting algorithm Sufficient Writers measuring instruments Reactive power Device Panel device test LOAD

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DETECTION OF TECHNOGENIC RADIONUCLIDES AT LOW CONCENTRATIONS WHEN MONITORING NUCLEAR POWER PLANT EMISSIONS USING AN ARMS SPECTROMETRIC CHANNEL

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ATOMIC ENERGY 2010年第1期108卷 70-78页

作者： Korolev, S. A. Lavrukhin, Yu. E. Rumyantsev, O. V. Russian Acad Sci GEOKhI RAN Vernadskii Inst Geochem & Analyt Chem Moscow Russia

The application of statistical algorithms in the problem of early detection of technogenic, nuclear power plant emissions in the atmosphere near the ground by means of the spectrometric channel of ARMS ( Automatic Radiation Monitoring System) is examined. It is noted that the changes in the radon progeny content which are associated with the diurnal behavior of the intensity of turbulent mixing influence the variance of the readings in the (131)I and (137)Cs detection ranges. As a result, when a stationary Poisson model is used in the algorithm the number of false alarms increases and the algorithm becomes ineffective. Regional corrections lowering the probability of false alarms to <= 10(-3) with correct detection probability >= 0.7 were introduced into the detection and classification algorithm on the basis of the results of monitoring performed over the course of a year for intervals with stationary gamma background.

关键词： atmosphere reading Early Diagnosis diurnal animal sorting algorithm Variance Nuclear powerplants False alarms Arms algorithms ground turbulent mixing RADON PROGENY

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Classification of multisource remote sensing imagery using a Genetic algorithm and Markov random fields

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 1999年第3期37卷 1255-1260页

作者： Tso, BCK Mather, PM Univ Nottingham Sch Geog Nottingham NG7 2RD England

The use of contextual information for modeling the prior probability mass function has found applications in the classification of remotely sensed data, With the increasing availability of multisource remotely sensed data sets, random field models, especially Markov random fields (MRF), have been found to pro,ide a theoretically robust yet mathematical tractable way of coding multisource information and of modeling contextual behavior. It is well known that the performance of a model is dependent both on its functional form (in this case, the classification algorithm) and on the accuracy of the estimates of model parameters, In dealing with multisource data, the determination of source weighting and MRF model parameters is a difficult issue. We extend the methodology proposed in [1] by demonstrating that the use of an effective search procedure, the Genetic algorithm, leads to improved parameter estimation and hence higher classification accuracies.

关键词： model parameters remote-sensing data sorting algorithm remote sensing mass function Parameter estimation Markov random fields Genetic algorithm (GA)

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Blind modulation classification algorithm based on machine learning for spatially correlated MIMO system

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IET COMMUNICATIONS 2017年第7期11卷 1000-1007页

作者： Liu, Xiaokai Zhao, Chenglin Wang, Pengbiao Zhang, Yang Yang, Tianpu Beijing Univ Posts & Telecommun Sch Informat & Commun Engn Beijing Peoples R China Dept China Mobile Grp Design Inst Co Ltd Beijing Peoples R China

Spatial correlation is a decisive factor for pragmatic multiple-input multiple-output (MIMO) system, simultaneously bringing about some problems in the received signal modulation identification respect. In this study, the authors focus on blind digital modulation identification in the spatially correlated MIMO system and deliver a robust signal recognition algorithm based on extreme learning machine (ELM) and higher order statistical features for MIMO signal identification without a priori knowledge of the channel and signal parameters. The superiority of ELM lies in random selections of hidden nodes and ascertains output weights analytically, which result in lower computational complexity. Theoretically, this algorithm has a tendency to supply excellent generalisation performance at staggering learning rate. Further, the simulation results indicate that the ELM could reap a perfectly acceptable recognition performance and thus provides a solid ground structure for tackling MIMO modulation challenges in low signal-to-noise ratio.

关键词： sorting algorithm multiple input multiple output systems signal parameter signal recognition

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SAR image classification based on alpha-stable distribution

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REMOTE SENSING LETTERS 2011年第1期2卷 51-59页

作者： Peng, Yijin Xu, Xin Zhou, Wanbin Zhao, Yin Wuhan Univ Signal Proc Lab Sch Elect Informat Wuhan 430079 Hubei Peoples R China

We propose a classification algorithm that utilizes the alpha-stable distribution to model the texture features of synthetic aperture radar (SAR) images. The SAR image is first decomposed by stationary wavelet transform (SWT). After that, the alpha-stable distribution is applied to model the high-frequency subband coefficients of the image at each decomposition scale. A regression-type method is then used to estimate the alpha-stable distribution parameters, which form a feature vector that fully describes the texture. Finally, a SAR image classification algorithm is derived by exploiting this feature vector based on the support vector machines (SVM) approach. Because different combinations of alpha-stable distribution parameters contribute to differences in classification precision, a multi-level SVM (MSVM) classification algorithm is also presented to address the issue. Experimental results indicate that the proposed SAR image classification algorithm is effective and the MSVM algorithm improves the classification performance. Moreover, our proposed algorithm has low computational cost as only a small number of the alpha-stable distribution parameters are processed.

关键词： sorting algorithm Synthetic aperture radar Support Vector Network Eigenvector Image classification images algorithms Imagery (Psychotherapy) Rescue SAFETY ANALYSIS REPORTS distributed parameter Specific absorption rate

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Development of a sky imager for cloud cover assessment

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2008年第1期25卷 29-39页

作者： Cazorla, A. Olmo, F. J. Alados-Arboledasl, L. Univ Granada Ctr Andaluz Medio Ambiente Grp Fis & Atmosfera E-18071 Granada Spain Univ Granada Fac Ciencias Dept Fis Aplicada E-18071 Granada Spain

Based on a CCD camera, we have developed an in-house sky imager system for the purpose of cloud cover estimation and characterization. The system captures a multispectral image every 5 min, and the analysis is done with a method based on an optimized neural network classification procedure and a genetic algorithm. The method discriminates between clear sky and two cloud classes: opaque and thin clouds. It also divides the image into sectors and finds the percentage of clouds in those different regions. We have validated the classification algorithm on two levels: image level, using the cloud observations included in the METAR register performed at the closest meteorological station, and pixel level, determining whether the final classification is correct. (c) 2007 Optical Society of America.

关键词： sorting algorithm cloud cover Charge Coupled Device camera images imaging instrument sky Clouds Imagery (Psychotherapy) Sectoring

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Design and control of battery charger for electric vehicles using modular multilevel converters

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IET POWER ELECTRONICS 2021年第1期14卷 140-157页

作者： Quraan, Mahran Abu-Khaizaran, Muhammad Sa'ed, Jaser Hashlamoun, Wael Tricoli, Pietro Birzeit Univ Dept Elect & Comp Engn Ramallah Palestine Univ Birmingham Sch Elect Elect & Syst Engn Birmingham W Midlands England

Double-star modular multilevel converters with embedded battery cells are a ground breaking technology for the power converter of electric vehicles. In this topology, the battery cells are connected in series via half bridge DC-DC buck converter and can be independently discharged and recharged. This paper proposes a novel control system for this converter topology that can charge the battery cells from the grid at unity power factor and instantaneously balance them in terms of their state of charges without affecting the grid voltages and currents. The grid current controller is designed and implemented in the stationary reference frame using a proportional-resonant controller, while the state of charge balancing algorithm is designed using sorting algorithm and circulating current control. The simulation and experimental results have demonstrated that the proposed control strategy can effectively charge the battery cells with a negligible distortion of the grid current and can ensure the balance of cells during the recharge without affecting the grid current.

关键词： power converter power factor electric vehicles double-star modular multilevel converters Control of electric power systems novel control system proportional-resonant controller unity power factor control strategy sorting algorithm half bridge DC-DC buck converter embedded battery cells grid voltages Current control DC-DC power convertors power grids Transportation electric current control power convertors charge balancing algorithm circulating current control Power convertors and power supplies to apparatus battery chargers battery charger converter topology grid current controller Power electronics, supply and supervisory circuits

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Modeling a Problem-Solving Approach Through Computational Thinking for Teaching Programming

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IEEE TRANSACTIONS ON EDUCATION 2024年第2期67卷 282-291页

作者： Zebel-Al Tareq Yusof, Raja Jamilah Raja Univ Malaya Fac Comp Sci & Informat Technol Dept Software Engn Kuala Lumpur 50306 Malaysia

Contribution: A problem-solving approach (PSA) model derived from major computational thinking (CT) concepts. This model can be utilized to formulate solutions for different algorithmic problems and translate them into effective active learning methods. Background: Different teaching approaches for programming are widely available;however, being able to formulate an algorithmic solution computationally and then transform it into code is essential for students. Research Questions: What are the effective teaching approaches for fostering the development of problem-solving and programming skills? How do CT concepts contribute to the formulation of a PSA model for programming problems and its translation into an effective teaching method? How can an effective teaching method that utilizes the PSA model be identified and distinguished from other approaches? Methodology: A preliminary study pointed out the difficulties experienced when teaching programming, inspiring the formulation of a PSA model that used CT concepts. An experimental study on problem-based and game-based programming workshops that utilized the PSA model through sorting algorithms was performed on experimental groups consisting of 30 students each. A syntax-based programming workshop consisting of 30 students was used as the control group. All the participants were recruited through a pretest that incorporated basic programming questions. The participants had to answer a posttest after the workshop. Findings: The results showed that the participants exhibited no significant difference between the pretest and posttest for the syntax-based learning (SBL). However, there is a significant difference between the pretest and posttest of both the problem-based learning (PBL) and the game-based learning (GBL) workshops. There was no significant difference significant difference for the pretest scores of all three workshops. The analysis of the posttest further confirmed that the experimental groups (PBL and GBL)

关键词： Programming profession Education Problem-solving sorting Computational modeling Conferences Software algorithms Active learning approach model computational thinking (CT) computer science computing skills game-based learning (GBL) problem-based learning (PBL) problem-solving instructional methods sorting algorithm syntax-based learning (SBL)

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