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28 February 2017, Volume 22 Issue 1 Previous Issue    Next Issue

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Separation and Visualization of Arteries and Heart in 3D Computed Tomography Angiography Images LAN Shouren (兰守忍), CUI Chaoyi (崔超毅), LIU Xin (刘鑫), JOHNSON Shane,SU Jialiang (苏佳良), CHEN Benzhi (陈本智), WANG Lisheng* (王利生) 2017, 22 (1):  1-009.  doi: 10.1007/s12204-017-1792-x Abstract ( 645 )   The visualization of arteries and heart usually plays a crucial role in the clinical diagnosis, but researchers face the problems of region selection and mutual occlusion in clinical visualization. Therefore, the arteries and the heart cannot be easily visualized by current visualization methods. To solve the problems, we propose a new framework for arteries and cardiac visualization by combining a priori knowledge and the set operations. Firstly, a suitable region can be easily determined in the transfer function space with a priori knowledge and the visual feedback results. Secondly, the arteries and the heart can be directly extracted by the marked seed point. Finally, the arteries and the heart are separated for solving mutual occlusion through the set operations. This framework can easily solve the mutual occlusion problem in clinical visualization and greatly improve the region selection method in the transfer function space. Its effectiveness has been demonstrated on the basis of many experimental results. References | Related Articles | Metrics

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A Simple Screening Method for Analysis of Cell Adhesive Strength Cultured on Zein Microspheres YANG Hui (杨 辉), LI Weiying (李伟迎), WANG Jinye* (王瑾晔) 2017, 22 (1):  10-014.  doi: 10.1007/s12204-017-1793-9 Abstract ( 530 )   Cell adhesion plays an important role in the microcarrier culture. Therefore, it is necessary to find a simple method to evaluate the cell adhesive strength. By the glycerol method, we prepared zein microcarriers. Both microcarrier surface morphology and cells on the microcarriers could be observed clearly when the microcarriers and the cells were stained by acridine orange (AO). Pre-treatment of soaking and sterilizing processes was necessary for cell culture, but it did not alter the morphology of zein microcarriers. Three kinds of cells were cultured on zein microcarriers for 24 h. Vero cells showed the strongest adhesion, while L929 cells were easily detached from the microcarriers after a simple beating operation. The proliferation curve of Vero cells cultured on the microcarriers displayed no difference with that on Cytodex 1. References | Related Articles | Metrics

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Multi-Scale Simulation for the Forming of a Heavy Vessel Head Considering the Evolution of Defects and Microstructure YU Qiqi (俞奇奇), DONG Dingqian (董定乾), LI Xinjia(李馨家),SHANG Xiaoqing (尚晓晴), FENG Chao (冯 超), CUI Zhenshan*(崔振山) 2017, 22 (1):  15-023.  doi: 10.1007/s12204-017-1794-8 Abstract ( 634 )   The head of nuclear pressure vessel is a key component to guarantee the safety of nuclear power plant, so it is necessary to improve its mechanical properties during manufacturing. In the practical production, due to the huge size of the ingots from which the head is manufactured, coarse grains and voids are common defects existing in the material. Furthermore, cracks may appear in the forming process. It is highly demanded that the forming process must be properly designed with suitable parameters to compact the voids, to refine and homogenize the grains and to avoid cracks. Therefore, the research on the evolution of internal voids, grain size and cracks is very important to determine the forming process of huge components. SA508-3 steel is the material to manufacture the head of pressure vessel in the nuclear island. In the previous studies, we have separately built models to evaluate the evolution of internal voids, grain size and cracks during the hot forming process for SA508-3 steel. This study integrates the models for multi-scale simulation of the forging process of the head of nuclear pressure vessel in order to control the quality of the forgings. Through the software development, the models are integrated with a commercial finite element code DEFORM. Then, the extended forging and final forging processes of the head are investigated, and some appropriate deformation parameters are recommended. References | Related Articles | Metrics

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Study on Dynamic Characteristics of Vehicle Gearbox Under Multi-Boundary Conditions FU Shengping (符升平), LUO Ning* (罗 宁), LI Shengbo (李胜波) 2017, 22 (1):  24-034.  doi: 10.1007/s12204-017-1795-7 Abstract ( 536 )   With the development of vehicle gearbox to high-power-density and high-speed, how to predict and optimize the dynamic characteristics of vehicle gearbox becomes increasingly prominent. Aiming at the vehicle gearbox, this paper comprehensively and deeply studies the dynamic characteristics under the multi-boundary conditions. The generation mechanism of the multi-source excitations triggering the gearbox vibration is analyzed firstly. The vibration transfer path of the gearbox is explored. Secondly, the engine excitation, the gear meshing excitation and the bearing support load are numerically calculated. According to the finite element method, a fluid-solid coupling finite element model of the gearbox body is established to predict the gearbox dynamic responses based on the Galerkin method and the Hamiltonian variational principle. Finally, the effects of the excitation condition, oil height and reinforcement forms on the vibration responses of the gearbox body are thoroughly studied by simulation. The analysis indicates that it not only helps to modify and improve the method of forecasting the gearbox dynamic response, and also provides the theoretical and technical guidance for the gearbox design and optimization. References | Related Articles | Metrics

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Hydraulic Properties Analysis of the Unsaturated Cracked Soil CAO Ling1,2* (曹 玲), ZHANG Hua1 (张 华), CHEN Yong1 (陈 勇) 2017, 22 (1):  35-044.  doi: 10.1007/s12204-017-1796-6 Abstract ( 487 )   Morphological parameters of cracks significantly affect the hydraulic conductivity of cracked soil. A laboratory test was conducted to study the hydraulic properties of cracks. The dynamic development of cracks in soil during drying and wetting was measured in the test. Based on the test results, the relationships between the morphological parameters and the soil water content were quantified. According to the fractal model, the soil-water characteristic curve (SWCC) and permeability functions for the cracked soil were predicted based on the dynamical development process of the cracks. A crack-pore dual media model was established to simulate the ponding infiltration in the unsaturated cracked soil. The variations of the pore water pressure in different part of the fractal model are quite different due to the impact of the cracks. This result illustrates that the prediction of the hydraulic properties for the cracked soil is reasonable. References | Related Articles | Metrics

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Adaptive Illumination Normalization Approach Based on Denoising Technique for Face Recognition LIAN Zhichaoa,b* (练智超), SONG Jiea (宋 杰), LI Yanga (李 杨) 2017, 22 (1):  45-049.  doi: 10.1007/s12204-017-1797-5 Abstract ( 449 )   A novel adaptive illumination normalization approach is proposed to eliminate the effects caused by illumination variations for face recognition. The proposed method divides an image into blocks and performs discrete cosine transform (DCT) in blocks independently in the logarithm domain. For each block-DCT coefficient except the direct current (DC) component, we take the illumination as main signal and take the reflectance as “noise”. A data-driven and adaptive soft-thresholding denoising technique is employed in each block-DCT coefficient except the DC component. Illumination is estimated by applying the inverse DCT in the block-DCT coefficients, and the indirectly obtained reflectance can be used in further recognition task. Experimental results show that the proposed approach outperforms other existing methods. Moreover, the proposed method does not need any prior information, and none of the parameters can be determined by experience. References | Related Articles | Metrics

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Brittleness Analysis and Important Nodes Discovery in Large Time-Evolving Complex Networks ZHANG Honga* (张 红), HU Changzhenb (胡昌振), WANG Xiaojuna (王小军) 2017, 22 (1):  50-054.  doi: 10.1007/s12204-017-1798-4 Abstract ( 526 )   The brittleness analysis and important nodes detection have been a hot spot in the complex networks. How to get the overall feature of the whole network and how to find out some important nodes are requisites to solve these problems. In this paper, we adopt the trace of the adjacency matrix and the centrality of the complex networks to give a quantitative and qualitative analysis of networks being studied. Results show that the k-shell plays a more important role than the degree centrality and the betweenness in finding important nodes, and it can also be used to give direction on the immunization and maintenance of complex networks. References | Related Articles | Metrics

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Geometric Calibration Algorithm of Polarization Camera Using Planar Patterns WANG Yujie* (王玉杰), HU Xiaoping (胡小平), LIAN Junxiang (练军想),ZHANG Lilian (张礼廉), HE Xiaofeng (何晓峰), FAN Chen (范 晨) 2017, 22 (1):  55-059.  doi: 10.1007/s12204-017-1799-3 Abstract ( 591 )   Polarization pattern provides additional information besides spectral signatures. It can be used in many applications, such as navigation, defect detection and object identification. A novel polarization camera composed of four synchronized cameras is proposed, and it can realize real-time polarization measurement. This study particularly concentrates on the geometric calibration of the system. The projection model is analyzed and the multi-camera calibration algorithm is proposed. Firstly, each camera is calibrated separately using planar patterns, and then the geometric calibration algorithms are performed. Due to the geometrical constraint, a global optimization method results in smaller estimation uncertainties. A mean rotation error of 0.025? and a mean translation error of 0.26mm are achieved after geometric calibration. The images are rectified to establish a correspondence among cameras and are combined to acquire the polarization measurement. The polarization pattern of the skylight is measured by the system and the results are consistent with the previous studies. References | Related Articles | Metrics

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Priority Based Data Reporting Algorithm in Wireless Sensor Networks ZENG Bin* (曾 斌), YAO Lu (姚 路), HU Wei (胡 炜) 2017, 22 (1):  60-065.  doi: 10.1007/s12204-017-1800-1 Abstract ( 525 )   A cluster-based organization with two phases to separate priority calculation and network activity operations is developed. In the election-state phase, clusters are organized by those nodes with sufficient residual energy level (REL) that are distributed as evenly as possible in the network. For each network round, each node decides its role (such as, cluster header (CH) or a normal node) and its priority level for activity operation. The priority level also affects the active/sleep scheduling in the node. In the steady-state phase, the positive priority levels of active nodes determine their activity order to avoid transmission collision, and to reduce redundant data transmission and sensing coverage. Since the data reporting to the sink is usually performed by a CH delivery chain, subsidiary CHs are selected to assist with data delivery and to share the loading of CHs. The formulae for computing priority levels are analyzed and verified by the examples with valid parameters. The experimental results show that the two phases efficiently consume node energy and achieve energy savings. References | Related Articles | Metrics

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Performance Modelling of Patient Flow Scheduling Through a Formal Method CHEN Xiao1* (陈潇), THOMAS Nigel2, DING Jie3 (丁 杰) 2017, 22 (1):  66-071.  doi: 10.1007/s12204-017-1801-0 Abstract ( 429 )   Smart environment is being used in many areas to deliver more services to individuals in a physical space, such as a hospital. In the UK, the National Health Service (NHS) provides free and high quality healthcare service for all residents. Smart hospital environment is able to support NHS and provide more convenience. Patient flow scheduling is a crucial section in a smart hospital environment. Smart hospital environment aims to provide a smart environment in the hospital to facilitate individual experience and improve the quality of healthcare service. First of all, this paper investigates a real world patient flow scenario of a hospital in the UK and models a general scheduling scheme based on the scenario using a compositional formal approach, i.e. performance evaluation process algebra (PEPA). This scheduling scheme uses an easy-implemented solution (the grouping scheme) to reduce the waiting queue in the hospital. Secondly, fluid flow analysis is used for the performance analysis by generating a set of ordinary differential equations (ODEs) in terms of the PEPA model. References | Related Articles | Metrics

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A Simple Method to Solve the Network Congestion for Spitial Architcture ZHANG Chao* (张 超), YU Mingyan (喻明艳), YANG Bing (杨 兵) 2017, 22 (1):  72-076.  doi: 10.1007/s12204-017-1802-z Abstract ( 501 )   Scheduling algorithm always plays an important role in the spatial architecture for the contradiction between the finite network bandwidth and the abundant execution resources. This article provides a simple method to solve the contention for network resource in one of the spatial architecture, i.e. the tera-op, reliable, intelligently adaptive processing system (TRIPS) processor. The method improves the performance of network by increasing the bypass bandwidth which can transmit the data in the internal of every execution unit, and converting the proportion of remote communication by the deep scheduling algorithm. The deeply optimized algorithm is realized to verify the validity of the method, and the performance increase 9% for floating point spec2000 benchmark is got. References | Related Articles | Metrics

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Weak Correlation Dictionary Construction Method for Sparse Coding LONG Haixia (龙海霞), ZHUO Li* (卓 力), QU Panling (屈盼玲), ZHANG Jing (张 菁) 2017, 22 (1):  77-081.  doi: 10.1007/s12204-017-1803-y Abstract ( 485 )   For sparse coding, the weaker the correlation of dictionary atoms is, the better the representation capacity of dictionary will be. A weak correlation dictionary construction method for sparse coding has been proposed in this paper. Firstly, a new dictionary atom initialization is proposed in which data samples with weak correlation are selected as the initial dictionary atoms in order to effectively reduce the correlation among them. Then, in the process of dictionary learning, the correlation between atoms has been measured by correlation coefficient, and strong correlation atoms have been eliminated and replaced by weak correlation atoms in order to improve the representation capacity of the dictionary. An image classification scheme has been achieved by applying the weak correlation dictionary construction method proposed in this paper. Experimental results show that, the proposed method averagely improves image classification accuracy by more than 2%, compared to sparse coding spatial pyramid matching (ScSPM) and other existing methods for image classification on the datasets of Caltech-101, Scene-15, etc. References | Related Articles | Metrics

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Chinese to Braille Translation Based on Braille Word Segmentation Using Statistical Model WANG Xiangdong1,3* (王向东), YANG Yang2 (杨阳), ZHANG Jinchao3 (张金超), JIANG Wenbin3 (姜文斌), LIU Hong1,3 (刘 宏), QIAN Yueliang1,3 (钱跃良 2017, 22 (1):  82-086.  doi: 10.1007/s12204-017-1804-x Abstract ( 509 )   Automatic translation of Chinese text to Chinese Braille is important for blind people in China to acquire information using computers or smart phones. In this paper, a novel scheme of Chinese-Braille translation is proposed. Under the scheme, a Braille word segmentation model based on statistical machine learning is trained on a Braille corpus, and Braille word segmentation is carried out using the statistical model directly without the stage of Chinese word segmentation. This method avoids establishing rules concerning syntactic and semantic information and uses statistical model to learn the rules stealthily and automatically. To further improve the performance, an algorithm of fusing the results of Chinese word segmentation and Braille word segmentation is also proposed. Our results show that the proposed method achieves accuracy of 92.81% for Braille word segmentation and considerably outperforms current approaches using the segmentation-merging scheme. References | Related Articles | Metrics

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Continuous Multiplicative Attribute Graph Model HUANG Jiaxuan (黄嘉烜), JIN Xiaogang* (金小刚) 2017, 22 (1):  87-091.  doi: 10.1007/s12204-017-1805-9 Abstract ( 654 )   Network modeling is an important approach in many fields in analyzing complex systems. Recently new series of methods have emerged, by using Kronecker product and similar tools to model real systems. One of such approaches is the multiplicative attribute graph (MAG) model, which generates networks based on category attributes of nodes. In this paper we try to extend this model into a continuous one, give an overview of its properties, and discuss some special cases related to real-world networks, as well as the influence of attribute distribution and affinity function respectively. References | Related Articles | Metrics

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Research of Legal Affair Simulation Based on Petri Net QU Zhenxin* (屈振新), WANG Mengzhu (王梦竹) 2017, 22 (1):  92-098.  doi: 10.1007/s12204-017-1806-8 Abstract ( 492 )   Legal affair simulation is on the basis of information technology, and can simulate legal scene. College students do legal experiments with virtual reality scene. This helps to train college students. Petri net has not only strict math definition to analyze the dynamic behavior of models, but also intuitive graphic expression. Petri net is used to model for legal process. Reduction rules of Petri net are used to analyze the correctness of the system. At last Java Business Process Management (JBPM) technology is used to realize legal affair simulation models, models are transformed into flow charts. Simulation software deduces processes of legal affair. Many college students have improved their ability with the software, the fact proves that the method is effective. References | Related Articles | Metrics

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Algorithm Based on Morphological Component Analysis and Scale-Invariant Feature Transform for Image Registration WANG Gang* (王 刚), LI Jingna (李京娜), SU Qingtang (苏庆堂)，ZHANG Xiaofeng (张小峰), L¨U Gaohuan (吕高焕), WANG Honggang (王洪刚) 2017, 22 (1):  99-106.  doi: 10.1007/s12204-017-1807-7 Abstract ( 498 )   In this paper, we proposed a registration method by combining the morphological component analysis (MCA) and scale-invariant feature transform (SIFT) algorithm. This method uses the perception dictionaries, and combines the Basis-Pursuit algorithm and the Total-Variation regularization scheme to extract the cartoon part containing basic geometrical information from the original image, and is stable and unsusceptible to noise interference. Then a smaller number of the distinctive key points will be obtained by using the SIFT algorithm based on the cartoon part of the original image. Matching the key points by the constrained Euclidean distance, we will obtain a more correct and robust matching result. The experimental results show that the geometrical transform parameters inferred by the matched key points based on MCA+SIFT registration method are more exact than the ones based on the direct SIFT algorithm. References | Related Articles | Metrics

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Performance Analysis of AF Relaying Based on Water-filling Power Allocation over Nakagami-m Fading QIN Dong* (秦 东), WANG Yan (王 炎) 2017, 22 (1):  107-113.  doi: 10.1007/s12204-017-1808-6 Abstract ( 405 )   This paper investigates exact performance of an amplify-and-forward (AF) relay system based on water-filling power allocation in Nakagami-m fading environment, where m is a nonnegative integer plus one half. We first offer the cumulative distribution function (CDF) and probability density function (PDF) of the received signal-to-noise ratio (SNR) at a destination. Then outage probability, moments of SNR, higher-order statistics of the capacity are explicitly conducted. Especially, average symbol error rate (SER) under an additive white generalized Gaussian noise (AWGGN) is developed for water-filling power allocation scheme. While the average SER subjected by an additive white Gaussian noise (AWGN) can be regarded as a special case. Finally, all theoretical formulas are truly attested by various simulation results. References | Related Articles | Metrics

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Compressive Sensing Reconstruction Based on Weighted Directional Total Variation MIN Lihua1*(闵莉花), FENG Can2 (冯 灿) 2017, 22 (1):  114-120.  doi: 10.1007/s12204-017-1809-5 Abstract ( 544 )   Directionality of image plays a very important role in human visual system and it is important prior information of image. In this paper we propose a weighted directional total variation model to reconstruct image from its finite number of noisy compressive samples. A novel self-adaption, texture preservation method is designed to select the weight. Inspired by majorization-minimization scheme, we develop an efficient algorithm to seek the optimal solution of the proposed model by minimizing a sequence of quadratic surrogate penalties. The numerical examples are performed to compare its performance with four state-of-the-art algorithms. Experimental results clearly show that our method has better reconstruction accuracy on texture images than the existing scheme. References | Related Articles | Metrics

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A Multiscale Superpixel-Level Salient Object Detection Model Using Local-Global Contrast Cue MU Nan1 (穆楠), XU Xin1,2* (徐 新), WANG Yinglin3 (王英林), ZHANG Xiaolong1,2 (张晓龙) 2017, 22 (1):  121-128.  doi: 10.1007/s12204-017-1810-z Abstract ( 567 )   The goal of salient object detection is to estimate the regions which are most likely to attract human’s visual attention. As an important image preprocessing procedure to reduce the computational complexity, salient object detection is still a challenging problem in computer vision. In this paper, we proposed a salient object detection model by integrating local and global superpixel contrast at multiple scales. Three features are computed to estimate the saliency of superpixel. Two optimization measures are utilized to refine the resulting saliency map. Extensive experiments with the state-of-the-art saliency models on four public datasets demonstrate the effectiveness of the proposed model. References | Related Articles | Metrics