40 results
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2. Computer Vision Algorithms for 3D Object Recognition and Orientation: A Bibliometric Study.
- Author
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Yahia, Youssef, Lopes, Júlio Castro, and Lopes, Rui Pedro
- Subjects
OBJECT recognition algorithms ,COMPUTER algorithms ,SCIENTIFIC literature ,DEEP learning ,OBJECT recognition (Computer vision) ,BIBLIOMETRICS ,POINT cloud ,COMPUTER vision ,LASER based sensors - Abstract
This paper consists of a bibliometric study that covers the topic of 3D object detection from 2022 until the present day. It employs various analysis approaches that shed light on the leading authors, affiliations, and countries within this research domain alongside the main themes of interest related to it. The findings revealed that China is the leading country in this domain given the fact that it is responsible for most of the scientific literature as well as being a host for the most productive universities and authors in terms of the number of publications. China is also responsible for initiating a significant number of collaborations with various nations around the world. The most basic theme related to this field is deep learning, along with autonomous driving, point cloud, robotics, and LiDAR. The work also includes an in-depth review that underlines some of the latest frameworks that took on various challenges regarding this topic, the improvement of object detection from point clouds, and training end-to-end fusion methods using both camera and LiDAR sensors, to name a few. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Research on Material Demand Forecasting Algorithm Based on Multi-Dimensional Feature Fusion.
- Author
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She, Shi-Yao, Yuan, Fang-Fang, Li, Jun-Ke, and Dai, Hong-Wei
- Subjects
FORECASTING ,COMPUTER algorithms ,VECTOR analysis ,NEURAL computers - Abstract
Material demand forecasting has a profound impact on the supply chain and is an important prerequisite for manufacturing enterprises to produce. In order to accurately predict the material demand of enterprises, this paper proposes a material demand forecasting algorithm based on multi-dimensional feature fusion (DFMF). Secondly, in order to obtain the spatial features, the vector representation of the relevant materials of a material is obtained through the attention mechanism. Then, the authors aggregate the relevant material representation and material vector representation of materials to obtain the final material vector representation through aggregation function. Then the final material vector representation under different time scales is used as input, and the prediction value of material demand is obtained by using BP neural network. Finally, experiments show that the model can effectively obtain multi-dimensional features of materials for prediction, and the prediction results have high accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. A Multiplayer Virtual Intelligent System Based on Distributed Virtual Reality.
- Author
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You, Zhen, Huang, Jiewen, Xue, Jinyun, Chen, Jiaxiang, Liu, Jiaxin, Yu, Qihong, and Hu, Hongwen
- Subjects
COMPUTER algorithms ,HERITAGE tourism ,TOURIST attractions ,VIRTUAL networks ,BEHAVIORAL research ,VIRTUAL reality - Abstract
Distributed Virtual Reality (DVR) is a combination of network and virtual reality technology, it could facilitate to construct a uniformly shared Distributed Virtual Environment (DVE) by using network to connect geographically distributed multiplayers. This paper concentrates on the theoretical research and practical development about Multiplayer Virtual Intelligent System (MVIS), and the main contribution could be summarized as two points. (1) Based on the DVR technology, this paper presented some theoretical research on MVIS, including the classification of virtual entities, communication pattern of entities, and the behavioral consistency research. Furthermore, a Multiplayer Earliest Deadline First (MEDF) program was proposed in order to guarantee the consistency of entities. (2) A prototype algorithm experiment system, called Multiplayer Graph-algorithm Intelligent System (MGIS), was designed. MGIS not onlyefficiently solves many problems in traditional computer algorithm teaching, such as high-abstraction, difficulty to understand, and lack of interaction mechanism; but also extends the application of DVR to cultural tourism, because MGIS is developed on the 3D scene of Lushan Mountain, which is one of the notable tourist attractions in China, and was included in the UNESCO World Heritage list in 1996. What i's more, MGIS illustrates the ability of expression, applicability and generality of the theoretical research about MVIS. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. Safety Design and Engineering Solution of Fuel Cell Powered Ship in Inland Waterway of China.
- Author
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Lijian Chen and Wenfeng Guan
- Subjects
FUEL cells ,WATERWAYS ,ELECTRIC connectors ,COMPUTER algorithms - Abstract
From the perspective of risk control, when hydrogen fuel and fuel cells are used on ships, there is a possibility of low-flash fuel leakage, leading to the risk of explosion. Since the fuel cell space (cabin for fuel cell installations) is an enclosed space, any small amount of leakage must be handled properly. In ship design, area classification is a method of analyzing and classifying the areas where explosive gas atmospheres may occur. If the fuel cell space is regarded as a hazardous area, all the electrical devices inside it must be explosion-proof type, which will make the ship's design very difficult. This paper takes a Chinese fuel cell powered ship as an example to analyze its safety. Firstly, the leakage rates of fuel cell modules, valves, and connectors are calculated. Secondly, the IEC60079-10-1 algorithm is used to calculate the risk level of the fuel cell space. Finally, the ship and fuel cells are optimized and redesigned, and the risk level of the fuel cell space is recalculated and compared. The result shows that the optimized fuel space risk level could be reduced to the level of the non-hazardous zone. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
6. A Novel Algorithm for Analysis of Buyer Satisfaction for the Third Party Logistics in C2C E-Commerce Market.
- Author
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Qinghua Zhang
- Subjects
COMPUTER algorithms ,CUSTOMER satisfaction ,THIRD-party logistics ,ELECTRONIC commerce ,QUESTIONNAIRES ,BUSINESS enterprises - Abstract
The development level of logistics has been far more behind the demand for E-commerce development and logistics is becoming the bottle neck restricting the E-commerce development of China. In this paper, we focus on buyer satisfaction for the third party logistics in C2C E-commerce market, based on the ORC model, put forward correlative hypotheses and verified the model and hypotheses by means of questionnaire survey and data analysis. The research results are that under C2C net shopping background, operation quality shows no significant positive effect, relationship quality shows less significant positive effect and cost quality shows significant positive effect to buyer satisfaction for the third party logistics, and relationship quality shows significant positive effect to operation quality and cost quality. In C2C E-commerce market, the third party logistics enterprises can take the research results as reference if they intend to improve customer satisfaction degree and obtain further development. [ABSTRACT FROM AUTHOR]
- Published
- 2012
7. 多尺度双通道卷积神经网络下的刺绣模拟.
- Author
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钱文华, 普园媛, 徐丹, and 李宗彦
- Subjects
ARTISTIC style ,COMPUTER algorithms ,EMBROIDERY ,MOTOR ability ,HANDICRAFT - Abstract
Copyright of Journal of Image & Graphics is the property of Editorial Office of Journal of Image & Graphics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
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8. Multi-scale Representation of Global Vector Data on Sphere Based on Map Accuracy.
- Author
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Fang Lin and Hu Bailin
- Subjects
VECTOR data ,ACCURACY of information ,GEOSPATIAL data ,DIMENSIONAL analysis ,GEOGRAPHIC information systems ,COMPUTER algorithms - Abstract
With the application of large scale even global scale geospatial data, the multi-scale representation of global vector data on sphere becomes very important. In order to represent the multi-scale global vector data efficiently and accurately, a real-time global vector data simplification method based on map accuracy is presented in this paper. Firstly, this method generates simplification thresholds according to the principle of map accuracy and the distance between viewpoint and the 3D global surface. Then, an improved-Li-Openshaw algorithm and Daglaus- Peauker algorithm are used to simplify line objects in two different directions in the data multi-scale representation process. Finally, an experiment with ESRI shp file data of the roads in China is given. The result illustrates that the method can simplify line objects efficiently, and the simplification ratio can reach about 80% or higher. The result is good and receivable. [ABSTRACT FROM AUTHOR]
- Published
- 2010
9. Application of back-propagation neural network on bank destruction forecasting for accumulative landslides in the three Gorges Reservoir Region, China.
- Author
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Li, Changdong, Tang, Huiming, Ge, Yunfeng, Hu, Xinli, and Wang, Liangqing
- Subjects
GORGES ,LANDSLIDES ,ARTIFICIAL neural networks ,RAINFALL ,ALTITUDES ,BOREHOLES ,COMPUTER algorithms - Abstract
In recent years, a large number of bank destruction occur in the reservoir area under the effect of water fluctuation, which may be lead to reservoir accumulative landslide geological hazards finally. The paper conducted the bank destruction forecasting study for accumulative landslides in the Three Gorges Reservoir Region, China utilizing back-propagation (BP) neural network approach. A representative scenario of Jinle landslide is then taken for analysis purposes. On the basis of the existing data sets of bank destruction cases, the BP neural network forecasting model and the corresponding programs for bank destruction are both presented, whose forecasting result is validated by two independent approaches, namely empirical method and numerical modeling method. Furthermore, the BP neural network model had obvious advantages over the convention approaches in the aspects of the fast calculation speed and high convenience. According to the bank destruction forecasting scale presented above, the corresponding revetment measures can be proposed to prevent the occurring of the bank destruction, whose effectiveness has been further validated by the actual engineering practice. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
10. Dynamic Computable General Equilibrium Model and Sensitivity Analysis for Shadow Price of Water Resource in China.
- Author
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Jing He, Xikang Chen, Yong Shi, and Aihua Li
- Subjects
WATER resources development ,SHADOW prices ,EQUILIBRIUM ,NATURAL resources ,COMPUTER algorithms ,PROJECT evaluation ,SCARCITY ,FACTORS of production - Abstract
A novel dynamic computable general equilibrium model based on National Water Resource Input Holding Output Table is proposed to calculate the Shadow Price of water resource in China. Unlike previous approaches, the dynamic Shadow Price of water resource is largely based on the scarcity extent and can reflect the marginal long-term value in the balanced growth path of China. Firstly, the basic concepts of dynamic Input Output analysis and Turnpike Theory are reviewed. Then, Dynamic Computable General Equilibrium (DCGE) is elaborated to calculate the Shadow Price, including the definition and computer-based algorithm. Furthermore, Shadow Price of water resource in China from 1949 to 2050 is calculated based on the DCGE. Also the sensitivity analysis of the DCGE for Shadow Price of water resource in China is presented. Dynamic Shadow Price of water resource has two meanings for China government: (1) Project evaluation. Every large-scale project in China must have national economic evaluation and the dynamic Shadow Price is prerequisite for national economic evaluation. (2) Market price of water resource. A lesson from this paper is that Shadow Price of water resource in domestic market of China should be rewritten according to the dynamic Shadow Price. In addition, the parallel computations approach could also be used to solve these problems in different countries or for different natural resources. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
11. Integrated civilian–military pre-positioning of emergency supplies: A multiobjective optimization approach.
- Author
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Zheng, Yu-Jun, Wang, Yue, Ling, Hai-Feng, Xue, Yu, and Chen, Sheng-Yong
- Subjects
EMERGENCY management ,MATHEMATICAL optimization ,SPECIAL operations (Military science) ,COMPUTER algorithms ,BIOGEOGRAPHY - Abstract
Emergency supplies pre-positioning is crucial to improve the speed of response and mitigate the effects of disasters. According to the requirements of emergency preparedness for both civilian and military operations in China, the paper presents a problem of integrated civilian–military emergency supplies pre-positioning, the aim of which is to maximize both the expected military operational efficiency and the expected civilian operational efficiency while minimizing the overall cost of pre-positioning. To solve the problem, the paper proposes a solution method that uses a multiobjective algorithm to evolve a population of main location solutions and uses another single-objective algorithm to search optimal allocation sub-solutions for each main solution. Among different heuristics, we select water wave optimization (WWO) to design a multiobjective algorithm for the main problem and select biogeography-based optimization (BBO) for the subproblem, and demonstrate that they have competitive performance advantage in comparison with a set of well-known algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
12. Estimating Wheat Yield in China at the Field and District Scale from the Assimilation of Satellite Data into the Aquacrop and Simple Algorithm for Yield (SAFY) Models.
- Author
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Silvestro, Paolo Cosmo, Pignatti, Stefano, Pascucci, Simone, Hao Yang, Zhenhai Li, Guijun Yang, Wenjiang Huang, and Casa, Raffaele
- Subjects
WHEAT yields ,AGRICULTURE ,LANDSAT satellites ,AGRICULTURAL management ,COMPUTER algorithms - Abstract
Accurate yield estimation at the field scale is essential for the development of precision agriculture management, whereas at the district level it can provide valuable information for supply chain management. In this paper, Huan Jing (HJ) satellite HJ1A/B and Landsat 8 Operational Land Imager (OLI) images were employed to retrieve leaf area index (LAI) and canopy cover (CC) in the Yangling area (Central China). These variables were then assimilated into two crop models, Aquacrop and simple algorithm for yield (SAFY), in order to compare their performances and practicalities. Due to the models’ specificities and computational constraints, different assimilation methods were used. For SAFY, the ensemble Kalman filter (EnKF) was applied using LAI as the observed variable, while for Aquacrop, particle swarm optimization (PSO) was used, using canopy cover (CC). These techniques were applied and validated both at the field and at the district scale. In the field application, the lowest relative root-mean-square error (RRMSE) value of 18% was obtained using EnKF with SAFY. On a district scale, both methods were able to provide production estimates in agreement with data provided by the official statistical offices. From an operational point of view, SAFY with the EnKF method was more suitable than Aquacrop with PSO, in a data assimilation context. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
13. Digital monitoring of grain conditions in large-scale bulk storage facilities based on spatiotemporal distributions of grain temperature.
- Author
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Wu, Wenfu, Cui, Hongwei, Han, Feng, Liu, Zhe, Wu, Xiaoming, Wu, Zidan, and Zhang, Qiang
- Subjects
- *
STORAGE facilities , *TEMPERATURE distribution , *GRAIN , *COMPUTER software testing , *GRAIN storage , *COMPUTER algorithms - Abstract
Managing large-scale facilities for storing bulk grain is time-consuming, labour intensive, and often difficult to be thorough. This paper presents a computer algorithm for using temperature data to remotely monitor and inspect stored grain in large bulk storage facilities. The algorithm is based on the analysis of the spatiotemporal distributions of the temperature field in the stored grain. The characteristics and irregularities of the temperature field were analysed to detect changes in grain quantity (inventory) and quality. The algorithm was implemented in computer software and tested on 234,300 sets of temperature data from 592 different grain depots in 10 provinces in China. The average accuracy of correctly identifying grain quality and inventory problems was 94%. • 234,300 sets of temperature data in large grain storage facilities were analysed. • Spatiotemporal distributions of grain temperature were related to grain conditions. • An algorithm was developed to identify grain quality and quantity issues in storage. • The average accuracy of identification of 592 grain storage facilities was 94%. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
14. Developing a cloud model based risk assessment methodology for tunnel-induced damage to existing pipelines.
- Author
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Zhang, Limao, Wu, Xianguo, Chen, Queqing, Skibniewski, Miroslaw, and Zhong, Jingbing
- Subjects
CRACKING of pipelines ,RISK assessment ,TUNNELS ,CLOUD computing ,RANDOM numbers ,COMPUTER algorithms - Abstract
This paper presents a cloud model (CM) based approach with step-by-step procedures for risk assessment of existing pipelines in tunneling environments (RAEPTE), where CM provides a basis for uncertainty transforming between qualitative concepts and their quantitative expressions. An evaluation index system of multiple layers and attributes is established for RAEPTE based upon the tunnel-induced pipeline failure mechanism analysis. The evaluation result is assessed by the correlation with CMs of each risk level. A confidence indicator is proposed to illustrate the reliability of evaluating results. Risk analysis for ten underground buried pipelines adjacent to the construction of Wuhan Metro Line Two in China is shown in a case study. Comparisons between different evaluation methods are further discussed according to results. The proposed approach is verified to be a more competitive solution, where the uncertainties of fuzziness and randomness are incorporated in the risk assessment system. This approach can serve as a decision tool for the safety risk assessment in other similar projects, and to increase the likelihood of a successful project in an uncertain environment. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
15. Extraction of loess shoulder-line based on the parallel GVF snake model in the loess hilly area of China
- Author
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Song, Xiaodong, Tang, Guoan, Li, Fayuan, Jiang, Ling, Zhou, Yi, and Qian, Kejian
- Subjects
- *
HYBRID systems , *MATHEMATICAL models , *COMPUTER algorithms , *CLUSTER analysis (Statistics) , *PARALLEL programming - Abstract
Abstract: Loess shoulder-lines are the most critical terrain feature in representing and modeling the landforms of the Loess Plateau of China. Existing algorithms usually fail in obtaining a continuous shoulder-line for complicated surface, DEM quality and algorithm limitation. This paper proposes a new method, by which gradient vector flow (GVF) snake model is employed to generate an integrated contour which could connect the discontinuous fragments of shoulder-line. Moreover, a new criterion for the selection of initial seeds is created for the snake model, which takes the value of median smoothing of the local neighborhood regions. By doing this, we can extract the adjacent boundary of loess positive–negative terrains from the shoulder-line zones, which build a basis to found the real shoulder-lines by the gradient vector flow. However, the computational burden of this method remains heavy for large DEM dataset. In this study, a parallel computing scheme of the cluster for automatic shoulder-line extraction is proposed and implemented with a parallel GVF snake model. After analyzing the principle of the method, the paper develops an effective parallel algorithm integrating both single program multiple data (SPMD) and master/slave (M/S) programming modes. Based on domain decomposition of DEM data, each partition is decomposed regularly and calculated simultaneously. The experimental results on different DEM datasets indicate that parallel programming can achieve the main objective of distinctly reducing execution time without losing accuracy compared with the sequential model. The hybrid algorithm in this study achieves a mean shoulder-line offset of 15.8m, a quite satisfied result in both accuracy and efficiency compared with published extraction methods. [Copyright &y& Elsevier]
- Published
- 2013
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16. Foliage Clumping Index Over China's Landmass Retrieved From the MODIS BRDF Parameters Product.
- Author
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Gaolong Zhu, Weimin Ju, Chen, J. M., Peng Gong, Bailing Xing, and Jingfang Zhu
- Subjects
PLANT canopies ,MODIS (Spectroradiometer) ,SATELLITE-based remote sensing ,REMOTE sensing in earth sciences ,REFLECTANCE spectroscopy ,COMPUTER algorithms - Abstract
The three-dimentional plant canopy architecture is often characterized using the foliage clumping index useful for ecological and land surface modeling. In this paper, an algorithm is developed to retrieve the foliage clumping index with the Moderate Resolution Imaging Spectroradiometer bidirectional reflectance distribution function (BRDF) parameter product (MCD43A1), which is generated using the RossThick-LiSparse Reciprocal (Ross-Li) model. First, the Ross-Li model is modified to improve the simulation of the reflectance at hotspot using the Polarization and Directionality of Earth Reflectance measurements as benchmarks to determine BRDF parameters. Then, the modified model (Ross-Li-H) is used to simulate the reflectance at hotspot and darkspot, which is used to calculate the normalized difference between hotspot and darkspot (NDHD). With the relationship between clumping index and NDHD simulated by the 4-Scale geometrical model, the clumping index over China's landmass at 500-m resolution is retrieved every 8 days during the period from 2003 to 2008. Finally, The effect of topography on the retrieved clumping index is corrected using a topographic compensation function calculated from the digital elevation model at 90-m resolution. The topographically corrected clumping index values correlate well with field measurements at five sites over China, indicating the feasibility of the algorithm for retrieving the clumping index from the MCD43A1 product. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
17. Adaptive Weighted Morphology Detection Algorithm of Plane Object in Docking Guidance System.
- Subjects
COMPUTER algorithms ,IMAGE processing ,DATA extraction ,AIRPORTS ,SCIENTIFIC experimentation ,COMPARATIVE studies ,PATTERN recognition systems - Published
- 2010
- Full Text
- View/download PDF
18. A VLSI-oriented algorithm and its implementation for AVS chroma interpolation
- Author
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Zhu, Bingqiang, He, Yun, and Mei, Shunliang
- Subjects
- *
DIGITAL video standards , *VIDEO compression standards , *CODING theory , *COMPUTER algorithms , *VERY large scale circuit integration , *MULTIMEDIA systems , *IMPULSE response , *DIGITAL filters (Mathematics) - Abstract
Abstract: AVS (audio video coding standard) is the latest multimedia coding standard of China. Similar to H.264/AVC, AVS adopted the technology of fractional-pel-accurate motion compensation, which enhanced the compression efficiency. To obtain fractional pels, 4-tap FIR filters and bilinear filters are used for luma and chroma interpolation respectively. Unlike the VLSI-optimized FIR filters which could be implemented by adders and shifters, the bilinear filter for chroma is not so convenient for direct VLSI implementation due to its multiplications. In this paper, we propose a VLSI-oriented algorithm named SHAM (x–y-separated halved-approaching method) to accomplish the bilinear filtering. The proposed SHAM algorithm adopts a halved-approaching method which is an addition-and-shift-only method and with simpler data path. VLSI structures are also provide to implement the SHAM algorithm in this paper. Experiments based on UMC process show that the SHAM algorithm could be implemented with about 48% less silicon area or at doubled frequency compared with the direct implementation of the bilinear filter. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
19. Searching Multiple Structural Changes of Chinese Stock Market via GMDH.
- Author
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Yixiang Tian and Li Zhou
- Subjects
GMDH algorithms ,STOCK exchanges ,STOCK price indexes ,COMPUTER algorithms ,COMPUTER programming - Abstract
This paper analyzes multiple structural changes by GMDH (Group Meth- ods of Data Handling), which have obvious advantages. Our method extends the model of Lumsdaine & Papell (1997), and it could be applied to the case of more than two structural changes. Because of simultaneously considering every structural change of the hypothesis, it is likely to be of particular relevance in practice. And it can decrease large investigation costs by MATLAB programming. What is more, we can select the criterion value of F incremental statistic to control the significance of the breaks, based on kinds of investigation intentions. And the empirical evidences on Shenzhen Composite Index are presented to illustrate the usefulness of our method. [ABSTRACT FROM AUTHOR]
- Published
- 2009
20. Effect of coding learning on the computational thinking of young Chinese children: based on the three-dimensional framework.
- Author
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Fu, Chanjuan, Hao, Xiaoxin, Shi, Donglin, Wang, Lin, and Geng, Fengji
- Subjects
ROBOTS ,COMPUTER programming ,COMPUTER algorithms ,CULTURAL identity - Abstract
Coding learning can promote the development of computational thinking (CT) in young children. The effect of coding learning on CT may vary between different cultures. However, it lacks studies to evaluate the effect of coding learning on the various dimensions of CT in young Chinese children. To provide insight into this question, we recruited children aged 5–6 years to participate in the quasi-experimental study involving an experimental group and a control group. The experimental group learned collaboration- and robot-based coding for 12 lessons, whereas children in the control group attended school learning activities. The two groups showed significant changes in CT concepts after coding learning, but the changes were not different between the two groups. In addition, coding learning positively influenced the development of CT practices, including algorithm and debugging skills. Finally, qualitative analyses showed that children could express, connect, and question after learning coding, suggesting that coding learning benefits the development of CT perspectives. To summarize, coding learning positively influences the ability to apply coding concepts to solve problems in practice and the perspectives about themselves and the world around them. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
21. Three Extensions of Tong and Richardson's Algorithm for Finding the Optimal Path in Schedule-Based Railway Networks.
- Author
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Xie, J., Wong, S. C., and Lo, S. M.
- Subjects
- *
RAILROAD design & construction , *RAILROAD travel , *COMPUTER algorithms , *TRANSPORTATION , *RAILROAD stations - Abstract
High-speed railways have been developing quickly in recent years and have become a main travel mode between cities in many countries, especially China. Studying passengers' travel choices on high-speed railway networks can aid the design of efficient operations and schedule plans. The Tong and Richardson algorithm that is used in this model offers a promising method for finding the optimal path in a schedule-based transit network. However, three aspects of this algorithm limit its application to high-speed railway networks. First, these networks have more complicated common line problems than other transit networks. Without a proper treatment, the optimal paths cannot be found. Second, nonadditive fares are important factors in considering travel choices. Incorporating these factors increases the searching time; improvement in this area is desirable. Third, as high-speed railways have low-frequency running patterns, their passengers may prefer to wait at home or at the office instead of at the station. Thus, consideration of a waiting penalty is needed. This paper suggests three extensions to improve the treatments of these three aspects, and three examples are presented to illustrate the applications of these extensions. The improved algorithm can also be used for other transit systems. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
22. Application of a Gradient Descent Continuous Actor-Critic Algorithm for Double-Side Day-Ahead Electricity Market Modeling.
- Author
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Huiru Zhao, Yuwei Wang, Sen Guo, Mingrui Zhao, and Chao Zhang
- Subjects
- *
ELECTRIC utilities , *ELECTRIC power systems , *COMPUTER algorithms , *BIDDING strategies , *DECISION support systems , *MARKOV processes - Abstract
An important goal of China's electric power system reform is to create a double-side day-ahead wholesale electricity market in the future, where the suppliers (represented by GenCOs) and demanders (represented by DisCOs) compete simultaneously with each other in one market. Therefore, modeling and simulating the dynamic bidding process and the equilibrium in the double-side day-ahead electricity market scientifically is not only important to some developed countries, but also to China to provide a bidding decision-making tool to help GenCOs and DisCOs obtain more profits in market competition. Meanwhile, it can also provide an economic analysis tool to help government officials design the proper market mechanisms and policies. The traditional dynamic game model and table-based reinforcement learning algorithm have already been employed in the day-ahead electricity market modeling. However, those models are based on some assumptions, such as taking the probability distribution function of market clearing price (MCP) and each rival's bidding strategy as common knowledge (in dynamic game market models), and assuming the discrete state and action sets of every agent (in table-based reinforcement learning market models), which are no longer applicable in a realistic situation. In this paper, a modified reinforcement learning method, called gradient descent continuous Actor-Critic (GDCAC) algorithm was employed in the double-side day-ahead electricity market modeling and simulation. This algorithm can not only get rid of the abovementioned unrealistic assumptions, but also cope with the Markov decision-making process with continuous state and action sets just like the real electricity market. Meanwhile, the time complexity of our proposed model is only O(n). The simulation result of employing the proposed model in the double-side day-ahead electricity market shows the superiority of our approach in terms of participant's profit or social welfare compared with traditional reinforcement learning methods. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
23. Semantic description method for face features of larger Chinese ethnic groups based on improved WM method.
- Author
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Wang, Yuangang, Duan, Xiaodong, Liu, Xiaodong, Wang, Cunrui, and Li, Zedong
- Subjects
- *
ETHNIC groups , *FACIAL expression , *SEMANTICS , *COMPUTER algorithms , *FEATURE extraction , *NEURAL computers - Abstract
In this paper, a semantic description method based on improved WM algorithm is proposed to characterize the facial features of larger Chinese ethnic groups. We firstly utilize the face landmarking technique to extract facial feature points automatically. Geometric features are defined with these detected landmarks, including distances, perimeters and areas. Then the WM method is improved to generate linguistic rule from facial geometric feature data, which implements semantic description for multi-ethnic facial characteristics. Finally, a case study of learning ethnicity from face with proposed method is investigated in CEFD database. The experiment results indicate that the linguistic rule base obtained by method is competitive in ethnicity recognition compared with method Naive Bayes, C4.5, Decision Table, Random Forest, Adaboost and Logistic regression in terms of accuracy and interpretability. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
24. Optimizing the 3D Distributed Climate inside Greenhouses Using Multi-Objective Optimization Algorithms and Computer Fluid Dynamics.
- Author
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Li, Kangji, Xue, Wenping, Mao, Hanping, Chen, Xu, Jiang, Hui, and Tan, Gang
- Subjects
FLUID dynamics ,CLIMATE in greenhouses ,COMPUTER algorithms ,PROCESS optimization ,ENERGY crops ,DISTRIBUTED algorithms - Abstract
As one of the major production facilities in agriculture, a greenhouse has many spatial distributed factors influencing crop growth and energy consumption, such as temperature field, air flow pattern, CO 2 concentration distribution, etc. By introducing a hybrid computational fluid dynamics–evolutionary algorithm (CFD-EA) method, this paper constructs a micro-climate model of greenhouse with main environmental parameters optimized. Considering environmental factors' spatial influences together with energy usage simultaneously, the optimal solutions of control variables for crop growth are calculated. A commercial greenhouse located in east China is chosen for the method validation. Field experiments using temperature/velocity sensor matrix are carried out for CFD accuracy investigation. On this basis, the proposed optimization method is employed to search for the optimal control variables and parameters corresponding to the environmental Pareto frontier. By the proposed multi-objective scheme, we believe the method can provide set point basis for the design and regulation of large/medium-sized greenhouse production with high spatial resolution. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
25. Visual Analysis of Multimodal Movie Network Data Based on the Double-Layered View.
- Author
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Tang, Ying, Yu, Jia, Li, Chen, and Fan, Jing
- Subjects
- *
WIRELESS sensor nodes , *DATA visualization , *GRAPH theory , *INTERNET users , *COMPUTER algorithms , *MOTION pictures - Abstract
Multimodal visualization of network data is a method considering various types of nodes and visualizing them based on their types, or modes. Compared to traditional network visualization of nodes of the same mode, the new method treats different modes of entities in corresponding ways and presents the relations between them more clearly. In this paper, we apply the new method to visualize movie network data, a typical multimodal graph data that contains nodes of different types and connections between them. We use an improved force-directed layout algorithm to present the movie persons as the foreground and a density map to present films as the background. By combining the foreground and background, the movie network data are presented in one picture properly. User interactions are provided including detailed pie charts visible/invisible, zooming, and panning. We apply our visualization method to the Chinese movie data from Douban website. In order to testify the effectiveness of our method, we design and perform the user study of which the statistics are analyzed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
26. Study and Design of Open Laboratory Management System Based on Fingerprint Measurement Identification.
- Author
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LU Chang
- Subjects
- *
HIGHER education , *LABORATORY management , *INTEGRATED Automated Fingerprint Identification System (U.S.) , *COMPUTER algorithms , *FINGERPRINT databases - Abstract
As the rapid development of the higher education in China, it is very urgent to open the laboratories in full time. But it also cause some management problems, particularly in flow and large population. The staffs are hard to make the schedules clear enough to deal with check-in. It is an urgent demand to deploy an open laboratory management system which should be based on the identification. This paper designes an open laboratory management system based on fingerprint measurement identification and use minutia fingerprint matching algorithm to realize automatic fingerprint detection identification, which makes the algorithm more robust to nonlinear deformation between two images by changing a stable window into an alterable one. Finally, it stduies the whole software implemenation process. It adoptes the FVC fingerprint database and live stimulation to make experiments on the automatic fingerprint identification algorithm and verified the availability of the system. [ABSTRACT FROM AUTHOR]
- Published
- 2013
27. A Method for Evaluating Sea Dike Safety.
- Author
-
Su, Huaizhi, Qin, Peng, and Qin, Zhihai
- Subjects
OCEAN engineering ,QUALITATIVE research ,INFORMATION theory ,DIKES (Engineering) ,COMPUTER algorithms - Abstract
To implement the maintenance and management of the sea dike engineering, the qualitative factors and quantitative factors need to be combined to evaluate the sea dike safety. Firstly, the evaluation index system and evaluation grading criterions of sea dike safety are established. Secondly, a new weight structure of evaluation indexes is proposed to combine the subjective weight and objective weight. Fuzzy Analytic Hierarchy Process method is used to determine the subjective weight and implement the qualitative analysis for sea dike safety. Projection Pursuit algorithm is introduced to calculate the objective weight and implement the quantitative analysis for sea dike safety. Based on the minimum relative information entropy principle, above two weights are combined. Thirdly, an evaluation model of sea dike safety is built with the improved Set Pair Analysis method. Finally, the proposed analysis method is used to assess one sea dike safety in China. It is shown that the combined weight can describe both the subjective information of expert experience and objective variation information of samples values, the uncertainty of information can be handled by the improved Set Pair Analysis method. The evaluation model has the clear physical concepts and intuitive modeling process. The calculation result is reasonable. The proposed method can be applied to sea dike safety evaluation and other complex systems evaluation as well. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
28. A new construction adder based on Chinese abacus algorithm
- Author
-
Yi, Shu-Chung
- Subjects
- *
COMPUTER algorithms , *ABACUS , *PREDICTION models , *COMPARATIVE studies , *INFORMATION technology , *BEADS , *MATHEMATICAL instruments , *COMPUTER science - Abstract
Abstract: A new construction adder based on Chinese abacus algorithm is presented in this paper. There are two kinds of beads used in this construction. Each column element has three higher beads with a weight of four and three lower beads with a weight of one. The proposed 32-bit adder contains eight column elements. The construction was simulated by the technology of TSMC 0.18μm CMOS process. Layout was also made by the same technology. The maximum delay of the 32-bit abacus adder is 0.91ns and 14% less than that of Carry Look-ahead Adders for 0.18μm technology. The power consumption of the abacus adder is 3.1mW and 28% less than that of Carry Look-ahead Adders for 0.18μm technology. Recent researches are compared with the proposed adder. The construction was also simulated by Predictive Technology Model. The PTM results also presented. The use of Chinese abacus approach offers a competitive technique with respect to other adders. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
29. The characteristics of clusters of weather and extreme climate events in China during the past 50 years.
- Author
-
Yang Ping, Hou Wei, and Feng Guo-Lin
- Subjects
CLUSTER analysis (Statistics) ,CLIMATE change ,RAINFALL ,ATMOSPHERIC temperature ,COMPUTER algorithms - Abstract
The pick-up algorithm by the k-th order cluster for the closest distance is used in the fields of weather and climactic events, and the technical terms clustered index and high clustered region are defined to investigate their temporal and spatial distribution characteristics in China during the past 50 years. The results show that the contribution of extreme high-temperature event clusters changed in the period from the 1960s to the 1970s, and its strength was enhanced. On the other hand, the decreasing trend in the clusters of low-temperature extremes can be taken as a signal for warmer winters to follow in the decadal time scale. Torrential rain and heavy rainfall clusters have both been lessened in the past 50 years, and have different cluster characteristics because of their definitions. Regions with high clustered indexes are concentrated in southern China. The spatial evolution of the heavy rainfall clusters reveals that clustered heavy rainfall has played an important role in the rain-belt pattern over China during the last 50 years. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
30. Wetland Landscape Classification Based on the BP Neural Network in DaLinor Lake Area.
- Author
-
Bao, YuHai and Ren, Jianbin
- Subjects
ARTIFICIAL neural networks ,REMOTE-sensing images ,WETLAND landscape design ,BACK propagation ,LAKES ,MAXIMUM likelihood statistics ,COMPUTER algorithms - Abstract
Abstract: With the applications of remote sensing in the study of wetland landscape is more and more extensive, computer automatic classification method appears especially important. In this paper, using TM remote sensing data in August 2008 year in Dalinor, Research to application of BP neural network and Traditional classification methods - maximum likelihood. Through the selection of training samples, Choice of training algorithm and Optimal number of hidden neurons to determine, the precision of BP neural network classification and the accuracy of maximum likelihood classification are compared, The results showed that BP neural network based on LM algorithm is better than the maximum likelihood method for classify to remote sensing image Higher accuracy. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
31. Local Color Transfer Algorithm Based on CTWC and the Application in Styled Rendering of Yunnan Heavy Color Painting.
- Author
-
Pu, Yuanyuan, Li, Weiwei, Liu, Xin, Min, Zhihong, and Xie, Shi
- Subjects
COLOR-field painting ,COMPUTER algorithms ,NUMERICAL calculations ,PIXELS ,ITERATIVE methods (Mathematics) - Abstract
Abstract: In this paper, a local color transfer algorithm based on CTWC (Color Transfer Weight Coefficients) is proposed. Firstly, interactively select one or more corresponding areas in the original image and the target image, those colors need to transfer. Secondly, use the low pass Butterworth filter function to calculate the CTWC of each selected areas in the original image. The CTWC represents the influence degree of color transformation of the pixels in the selected areas of the original image, and the value of CTWC is inversely proportional to the color statistical distance of the selected corresponding areas between the original and target image. Finally, the Reinhard Algorithm is improved by the calculation method of CTWC and gets the local color transfer algorithm based on CTWC. For multi-regional local color transfer, an iterative image merge method is proposed to fuse the multi-regional local color transformation''s result images. In the end, the color transfer is used for Yunnan heavy color painting digital simulation and stylized rendering and the results of experiment shows it can obviously improve the rendering effect. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
32. Optimizing reservoir features in oil exploration management based on fusion of soft computing.
- Author
-
Haixiang, Guo, Xiuwu, Liao, Kejun, Zhu, Chang, Ding, and Yanhui, Gao
- Subjects
PETROLEUM prospecting ,PETROLEUM reserves ,SOFT computing ,COMPUTER algorithms ,DATA mining ,OIL fields - Abstract
Abstract: This paper introduces concepts and algorithms for feature selection, surveys existing feature selection algorithms for classification and clustering, groups and compares different algorithms by a categorizing framework based on search strategies, evaluation criteria, and data mining tasks and provides guidelines in selecting feature selection algorithms. Search strategies include complete ones, sequential ones and random ones. Evaluation criteria includes filter, wrapper and hybrid. Data mining tasks include classification and clustering. Then, a feature selecting platform is proposed as an intermediate step based on the data and requirement of the task. According to the platform and categorizing framework, some appropriate algorithms are compared. At last, an experiment based on data oilsk81, oilsk83, oilsk85 wells of Jianghan oil fields in China was operated by using one of the appropriate algorithms. This algorithm utilizes fusion of soft computing methods to distinguish the key features of reservoir oil-bearing formation and establishes a model with fusion of soft computing methods to forecast these key features. The following part is the process: Firstly, use genetic algorithm (GA) and fuzzy c-means algorithm (GA-FCM) to reduce well log features of oil-bearing formation and to obtain the key features that can describe oil-bearing formation of reservoir. Secondly, fuse genetic algorithm with BP neural network (GA-BP) to construct the fusion model that forecasts these key features. GA-BP searches the inputs and optimal number nodes of hidden layer of BP neural network through GA to choose the optimal structure of BP neural network forecasting model. Then test effectiveness of the forecasting model with recognition accuracy of testing samples. Finally, the optimal model for forecasting key features can be obtained. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
33. Spoken language understanding using weakly supervised learning
- Author
-
Wu, Wei-Lin, Lu, Ru-Zhan, Duan, Jian-Yong, Liu, Hui, Gao, Feng, and Chen, Yu-Quan
- Subjects
- *
SUPERVISED learning , *CLASSIFICATION , *ORAL communication , *ACTIVE learning , *TRANSPORTATION , *INTERNET , *COMPUTER algorithms - Abstract
Abstract: In this paper, we present a weakly supervised learning approach for spoken language understanding in domain-specific dialogue systems. We model the task of spoken language understanding as a two-stage classification problem. Firstly, the topic classifier is used to identify the topic of an input utterance. Secondly, with the restriction of the recognized target topic, the slot classifiers are trained to extract the corresponding slot-value pairs. It is mainly data-driven and requires only minimally annotated corpus for training whilst retaining the understanding robustness and deepness for spoken language. More importantly, it allows that weakly supervised strategies are employed for training the two kinds of classifiers, which could significantly reduce the number of labeled sentences. We investigated active learning and naive self-training for the two kinds of classifiers. Also, we propose a practical method for bootstrapping topic-dependent slot classifiers from a small amount of labeled sentences. Experiments have been conducted in the context of the Chinese public transportation information inquiry domain and the English DARPA Communicator domain. The experimental results show the effectiveness of our proposed SLU framework and demonstrate the possibility to reduce human labeling efforts significantly. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
34. Variation in reference crop evapotranspiration caused by the Ångström–Prescott coefficient: Locally calibrated versus the FAO recommended
- Author
-
Liu, Xiaoying, Mei, Xurong, Li, Yuzhong, Wang, Qingsuo, Zhang, Yanqing, and Porter, John Roy
- Subjects
- *
PLANT water requirements , *AGRICULTURAL water supply , *EVAPOTRANSPIRATION , *AGRICULTURAL ecology , *COMPUTER algorithms , *VAPOR pressure - Abstract
Abstract: Accurate estimation of the reference crop evapotranspiration (ET 0) is investigated due to its critical role in affecting calculation of crop water use and efficiency in agricultural ecosystems. The main emphasis in this paper is to clarify the possible uncertainty in the estimation of ET 0 associated with using un-calibrated Ångström–Prescott (A–P) coefficients. We first calibrated the coefficients using long-term data records from 34 sites in the Yellow River basin in China, and then applied these coefficients to estimate short wave irradiance (R s ) and ET 0 at 16 sites to evaluate the difference in ET 0 between the FAO recommended and the locally calibrated. We found that the direct use of the FAO recommended coefficients significantly affected the estimation of ET 0 at most sites, which differed from −3% to 15% at daily scale and from −4% to 16% at monthly scale from the locally calibrated ones. These differences are comparable with or larger than those caused by some alternatives of the FAO recommended algorithms for net irradiance or vapor pressure, which further highlights the importance of using the locally calibrated coefficients. The degree of difference in ET 0 showed a significant threshold relation with altitude and longitude in such a way that relatively small impact lies around 2233m and 98°E, and away from these, the effect begins to increase. Given the large overestimation in water use as a consequence of the significant overestimation in ET 0 associated with the direct use of the FAO coefficients, especially in those high yield production areas with altitude <1200m, we developed several relationships between the A–P coefficient a, b, (a + b) and other easily obtainable factors (altitude, longitude and air temperature). A three-step procedure was recommended in applying these relations, which was (1) determine if calibration is needed or not for a given location; (2) estimate one of the A–P coefficients, either a or b if calibration is needed; (3) estimate the remaining coefficient using relations of (a + b) due to its higher coefficient of determination. In summary, we have revealed the errors and areas that are most affected when using the un-calibrated coefficients, and discussed the consequence of such error on agricultural production, and proposed practical solutions to avoid large errors. These results are intended to make the research community aware of such errors so that more appropriate choice of these coefficients is made. We hope that similar assessment will be done in other climates, contributing to managing water resources efficiently in water basins. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
35. Soil moisture mapping over the Chinese Loess Plateau using ENVISAT/ASAR data
- Author
-
Zhang, Tangtang, Wen, Jun, Su, Zhongbo, Velde, Rogier van der, Timmermans, Joris, Liu, Rong, Liu, Yuanyong, and Li, Zhenchao
- Subjects
- *
SOIL moisture , *SOIL mapping , *ARTIFICIAL satellites , *REMOTE sensing , *OPTICAL observations of artificial satellites , *SYNTHETIC apertures , *COMPUTER algorithms - Abstract
Abstract: In this paper, we used the available algorithm for soil moisture estimation over LOPEX05 (the Loess Plateau land surface process Experiment (2005)) area. The available algorithm used ENVISAT/ASAR AP mode VV polarization observational data at a low incidence angle and ground measured soil moistures. The ground measurements were performed in the summer of the 2005 during the LOPEX05 field campaign. The validated results indicate that an average difference between the soil moistures estimated from the microwave remote sensing and ground measurements is less than 0.02cm3/cm3, with a RMS error of 2.0%, and a maximum less than 0.04cm3/cm3. The algorithm was applied to the surface soil moisture mapping later. The results show that this algorithm is suitable for monitoring soil moisture information of the agricultural fields over the Chinese Loess Plateau, when ground land cover situation and the resolution of imagery data are taken into account. However, we also find that there are large differences over the steep slope region, the edge of mesa. The results are not acceptable for surface soil moisture estimation in these regions. Thus, the surface soil moisture retrieval in the steep slope region of the Loess Plateau need to be further investigated in the future. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
36. Drought characteristics over China during 1980–2015.
- Author
-
Shao, Dongguo, Chen, Shu, Tan, Xuezhi, and Gu, Wenquan
- Subjects
DROUGHTS ,ATMOSPHERIC temperature ,COMPUTER algorithms ,DATA analysis ,CALIBRATION - Abstract
The self‐calibrating Palmer drought severity index (scPDSI) was computed based on the four atmospheric reanalysis data sets combined with observational data over China during 1980–2015. The discrepancies of scPDSI among the four reanalysis data sets show the necessity of integrating multiple data sets. Drought characteristics, such as drought area, severity, duration, and frequency were examined based on multi‐data set mean scPDSI. The results reveal that significant drying trends are found in Qinghai‐Tibet Plateau, southwest, southeast and entire China. Drought area (drought severity) has increased (decreased) by about 1.16% (0.015%) per decade over entire China. Trends in drought duration, temporally averaged severity and frequency also indicate that droughts become more serious in each region during the past 36 years. The identification of drought events in each month by the clustering algorithm shows that droughts over China are more and more frequent. In addition, 65 separate drought events with the duration longer than 3 months were identified under the area threshold of 150,000 km
2 . Through severity‐area‐duration analysis, the 2005–2015 drought is found to be the prominent event. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
37. Himawari-8 Satellite Based Dynamic Monitoring of Grassland Fire in China-Mongolia Border Regions.
- Author
-
Na, Li, Zhang, Jiquan, Bao, Yulong, Bao, Yongbin, Na, Risu, Tong, Siqin, and Si, Alu
- Subjects
GRASSLAND fires ,REMOTE-sensing images ,ARTIFICIAL satellites ,DATA analysis ,COMPUTER algorithms - Abstract
In this study, we used bands 7, 4, and 3 of the Advance Himawari Imager (AHI) data, combined with a Threshold Algorithm and a visual interpretation method to monitor the entire process of grassland fires that occurred on the China-Mongolia border regions, between 05:40 (UTC) on April 19th to 13:50 (UTC) on April 21st 2016. The results of the AHI data monitoring are evaluated by the fire point product data, the wind field data, and the environmental information data of the area in which the fire took place. The monitoring result shows that, the grassland fire burned for two days and eight hours with a total burned area of about 2708.29 km
2 . It mainly spread from the northwest to the southeast, with a maximum burning speed of 20.9 m/s, a minimum speed of 2.52 m/s, and an average speed of about 12.07 m/s. Thus, using AHI data can not only quickly and accurately track the dynamic development of a grassland fire, but also estimate the spread speed and direction. The evaluation of fire monitoring results reveals that AHI data with high precision and timeliness can be highly consistent with the actual situation. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
38. An Exploration Study on Quality Performance Casual Path Model Based on BN Method.
- Author
-
Shoudong Lu and Guohua Zhou
- Subjects
RAILROADS ,BAYESIAN analysis ,COMPUTER algorithms - Abstract
According to MBNQA:1997 standard and scale, empirical data was obtained through a questionnaire survey from Chinese railway construction enterprise, and used Bayesian Networks for PC algorithm, the path model of the causal relationship between QMP and QP is acquired. The CPT parameter is obtained by EM algorithm, reasoning analysis and diagnosis research are conducted, and some conclusions and suggestions are drawn. Finally, the methodological and practical value of the BN model is discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
39. Hubs and Authorities in the World Trade Network Using a Weighted HITS Algorithm.
- Author
-
Deguchi, Tsuyoshi, Takahashi, Katsuhide, Takayasu, Hideki, and Takayasu, Misako
- Subjects
COMPUTER algorithms ,ECONOMIC globalization ,HYPERLINKS ,LINKED data (Semantic Web) ,ECONOMIC development ,INFORMATION science ,INFORMATION networks - Abstract
We investigate the economic hubs and authorities of the world trade network (WTN) from to , an era of rapid economic globalization. Using a well-defined weighted hyperlink-induced topic search (HITS) algorithm, we can calculate the values of the weighted HITS hub and authority for each country in a conjugate way. In the context of the WTN, authority values are large for countries with significant imports from large hub countries, and hub values are large for countries with significant exports to high-authority countries. The United States was the largest economic authority in the WTN from to . The authority value of the United States has declined since , and China has now become the largest hub in the WTN. At the same time, China's authority value has grown as China is transforming itself from the “factory of the world” to the “market of the world.” European countries show a tendency to trade mostly within the European Union, which has decreased Europe's hub and authority values. Japan's authority value has increased slowly, while its hub value has declined. These changes are consistent with Japan's transition from being an export-driven economy in its high economic growth era in the latter half of the twentieth century to being a more mature, economically balanced nation. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
40. Vicarious Radiometric Calibration of Ocean Color Bands for FY-3D/MERSI-II at Lake Qinghai, China.
- Author
-
Chen, Shengli, Zheng, Xiaobing, Li, Xin, Wei, Wei, Du, Shenda, and Guo, Fuxiang
- Subjects
OCEAN color ,INFRARED imaging ,CALIBRATION ,LAKES ,COMPUTER algorithms ,COMPUTER simulation - Abstract
To calibrate the low signal response of the ocean color (OC) bands and test the stability of the Fengyun-3D (FY-3D)/Medium Resolution Spectral Imager II (MERSI-II), an absolute radiometric calibration field test of FY-3D/MERSI-II at the Lake Qinghai Radiometric Calibration Site (RCS) was carried out in August 2018. The lake surface and atmospheric parameters were mainly measured by advanced observation instruments, and the MODerate spectral resolution atmospheric TRANsmittance algorithm and computer model (MODTRAN4.0) was used to simulate the multiple scattering radiance value at the altitude of the sensor. The results showed that the relative deviations between bands 9 and 12 are within 5.0%, while the relative deviations of bands 8, and 13 are 17.1%, and 12.0%, respectively. The precision of the calibration method was verified by calibrating the Aqua/Moderate-resolution Imaging Spectroradiometer (MODIS) and National Polar-orbiting Partnership (NPP)/Visible Infrared Imaging Radiometer (VIIRS), and the deviation of the calibration results was evaluated with the results of the Dunhuang RCS calibration and lunar calibration. The results showed that the relative deviations of NPP/VIIRS were within 7.0%, and the relative deviations of Aqua/MODIS were within 4.1% from 400 nm to 600 nm. The comparisons of three on-orbit calibration methods indicated that band 8 exhibited a large attenuation after launch and the calibration results had good consistency at the other bands except for band 13. The uncertainty value of the whole calibration system was approximately 6.3%, and the uncertainty brought by the field surface measurement reached 5.4%, which might be the main reason for the relatively large deviation of band 13. This study verifies the feasibility of the vicarious calibration method at the Lake Qinghai RCS and provides the basis and reference for the subsequent on-orbit calibration of FY-3D/MERSI-II. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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