Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 9601 - 9630 of 11603

Full-Text Articles in Artificial Intelligence and Robotics

Research On 3d Immersive Underground Laboratory Visualization System, Jiaxin Hou, Yadong Wu, Yangjie Xu, Xuejun Li, Wang Song, Dongzhou Du, Xiaorong Zhang Jan 2019

Research On 3d Immersive Underground Laboratory Visualization System, Jiaxin Hou, Yadong Wu, Yangjie Xu, Xuejun Li, Wang Song, Dongzhou Du, Xiaorong Zhang

Journal of System Simulation

Abstract: Deep geological disposal of high-level radioactive waste is the only internationally recognized and feasible method. The construction of underground laboratories is a complex engineering. To improve the intuitiveness and accuracy of comprehensive data analysis, an immersive underground laboratory 3D data visualization system is constructed. The system includes surface scenes, scene models with laboratory lanes and bedrooms, and designs scene roaming and visual interactive interaction of 3D data. The practical application shows that this system can not only facilitate the rapid construction and evaluation of underground laboratory design schemes, but also provide scientific basis for rapid decision-making of engineering construction …


Deep Learning Method For Hyperspectral Remote Sensing Images With Small Samples, Xiangbin Shi, Zhong Jian, Cuiwei Liu, Liu Fang, Deyuan Zhang Jan 2019

Deep Learning Method For Hyperspectral Remote Sensing Images With Small Samples, Xiangbin Shi, Zhong Jian, Cuiwei Liu, Liu Fang, Deyuan Zhang

Journal of System Simulation

Abstract: In order to solve the problem of large information dimension and fewer labeled training samples of hyperspectral remote sensing images, this paper proposes a hyperspectral remote sensing image classification framework HSI-CNN, which reduces the number of model parameters while maintaining the depth of neural network. Image pattern invariance and spectral channel contribution rate are analyzed, and the spectral redundancy information is reduced by principal component analysis. A full convolution neural network structure suitable for small sample hyperspectral remote sensing images is designed and the amount of network parameters is effectively reduced. Three kinds of HSI-CNN structures are proposed …


Design And Realization Of Behavior Tree In Weapon Equipment Virtual Maintenance Training System, Wensheng Xu, Wu Bo, Jianhong Jiang Jan 2019

Design And Realization Of Behavior Tree In Weapon Equipment Virtual Maintenance Training System, Wensheng Xu, Wu Bo, Jianhong Jiang

Journal of System Simulation

Abstract: To solve the problem of long development period of virtual maintenance training system for complicated weapon equipment, the 3D modeling, the behavior modeling and the decision modeling of virtual maintenance were studied. The behavior trees design model was applied to analyze, design and develop the system which was tested in the maintenance case of marching tensioning device of a certain weapon equipment. The scripting unit and the running efficiency of the behavior trees model in the case were tested. The test results showed that this design method with behavior tree model has better scalability and model description clarity, and …


A 3d Tree Visualization Of Network Data Based On Webvr, Lin Ding, Guoxin Huang, Xu Ying Jan 2019

A 3d Tree Visualization Of Network Data Based On Webvr, Lin Ding, Guoxin Huang, Xu Ying

Journal of System Simulation

Abstract: A new method of three dimensional tree-style visualization of network data is proposed in this paper based on cluster computing, which maps the network structure of clustered data to hierarchical tree structure. The number of nodes of a community is treated as the weight to improve the PhylloTrees' phyllotactic layout algorithm and the 3D visualization of network data is implemented based on WebVR. Friendly interactive manipulations are achieved in the immersive VR scene such as rotation, zooming, pan, picking, and transparent fade / highlight enhancement of different displaying. The experimental results show that our method can show not only …


Saliency Feature Extraction Method Based On Multi-Scale Region Covariance, Shimin Wang, Jihua Ye, Mingwen Wang, Jiali Zuo, Changhong Liu Jan 2019

Saliency Feature Extraction Method Based On Multi-Scale Region Covariance, Shimin Wang, Jihua Ye, Mingwen Wang, Jiali Zuo, Changhong Liu

Journal of System Simulation

Abstract: In order to solve the problem that the saliency detection target boundary is vague, the paper proposes a saliency feature extraction method based on multi-scale region covariance. This method firstly extracts the multi-scale features of an image, then combines region covariance to extract the image bottom features, calculates the image’s multi-scale uncertainty weights, and the weights are optimized for the final saliency features, which are obtained by fusion. In the paper, our proposed model compares the experimental results with the commonly used feature extraction algorithms. The experimental results show that the proposed algorithm is closer to the actual …


Vehicle Detection Method In Uav Aerial Video, Suqin Wang, Wenhao Shi, Zhaoxin Li, Tianlu Mao Jan 2019

Vehicle Detection Method In Uav Aerial Video, Suqin Wang, Wenhao Shi, Zhaoxin Li, Tianlu Mao

Journal of System Simulation

Abstract: The use of UAV aerial photography to obtain traffic information has many advantages like a flexible high mobility, comprehensive information and so on, which plays a vital role in the emergency response, anti-terrorism/battlefield and other environments. This paper proposes a method for vehicle detection in UAV aerial video. Aiming at the problem of UAV video image deflection, the image registration method based on SURF algorithm is used to correct the deflection of UAV hatching video according to the standard frame. The background and the moving vehicle are separated by the pixel-based adaptive segmentation algorithm to detect the moving …


Video Action Recognition Based On Key-Frame, Mingxiao Li, Qichuan Geng, Mo Hong, Wu Wei, Zhou Zhong Jan 2019

Video Action Recognition Based On Key-Frame, Mingxiao Li, Qichuan Geng, Mo Hong, Wu Wei, Zhou Zhong

Journal of System Simulation

Abstract: Video action recognition is an important part of intelligent video analysis. In recent years, deep learning methods, especially the two-stream convolutional neural network achieved the state-of-the-art performance. However, most methods simply use uniform sampling to get frames, which may cause the loss of information in sampling interval. We propose a segmentation method and a key-frame extraction method for video action recognition, and combine them with a multi-temporal-scale two-stream network. Our framework achieves a 94.2% accuracy at UCF101 split1, which is the same as the state-of-the-art method’s performance.


Person Retrieval Method Based On Image Caption, Yadong Li, Mo Hong, Shihao Wang, Zhou Zhong, Wu Wei Jan 2019

Person Retrieval Method Based On Image Caption, Yadong Li, Mo Hong, Shihao Wang, Zhou Zhong, Wu Wei

Journal of System Simulation

Abstract: Retrieve specific person in the surveillance scene is an important and urgent demand on the security field. In recent years, the method of image retrieval is mainly based on image content, which requires the image to be retrieved works as input and thus can’t meet the actual needs of surveillance and security. We propose a method of person retrieval based on image caption and present a new surveillance dataset SPCD which tags person caption. We verify the method in new dataset, the accuracy of gender, dress color and action respectively reaches 86.5%, 93.5% and 65.5%. This paper provides an …


Simulation Optimization Design Method Of Model Driven Aviation Command And Support System, Yongliang Luo, Zhihui Zhang, Zhang Jun, Yuanhui Qin Jan 2019

Simulation Optimization Design Method Of Model Driven Aviation Command And Support System, Yongliang Luo, Zhihui Zhang, Zhang Jun, Yuanhui Qin

Journal of System Simulation

Abstract: As a typical complex system, the design process of air command and security system (ACSS) is different from the existing design process of complex system because of more typical characteristics, such as functional complexity, process complexity and scene complexity. According to the design requirements of ACSS, a simulation optimization design method of model driven and process centered ACSS based on the theoretical method of system engineering is proposed, and the key enabling technologies are introduced, which include model-driven multi-view architecture design, process traction simulation of ACSS, efficient resource optimization and allocation technology, and so on. The simulation and …


Multidisciplinary Coupling Simulation System For Multi-Body Separation Process Of Near Space Vehicles, Tie Ming, Fang Hong, Yu Ying, Caihui Yu, Wang Ling, Dongfei Hu Jan 2019

Multidisciplinary Coupling Simulation System For Multi-Body Separation Process Of Near Space Vehicles, Tie Ming, Fang Hong, Yu Ying, Caihui Yu, Wang Ling, Dongfei Hu

Journal of System Simulation

Abstract: The simulation of coupling dynamics from multi-body movement, flow field and structural stress field plays a significant role in the separation system design for a near space vehicle. In this paper, an elastic-body based multidisciplinary and multi-physics coupling simulation approach is proposed for the vehicle separation process. A multidisciplinary separation simulation system is developed, where the dynamic finite element simulation method for stress field, the high performance numerical simulation method for flow field and the multi-body movement simulation are combined. The proposed simulation system provides an efficient and accurate way to verify the separation scheme and the …


Simulation Assessment Of Degradation System Reliability Under Imperfect Maintenance, Haidong Du, Junhai Cao, Shen Ying, Shangru Teng Jan 2019

Simulation Assessment Of Degradation System Reliability Under Imperfect Maintenance, Haidong Du, Junhai Cao, Shen Ying, Shangru Teng

Journal of System Simulation

Abstract: For the state change characteristic of degradation system under imperfect maintenance, the common analysis method becomes useless. A simulation method for repairable system is presented. A change rule of system reliability was analyzed and a reliability assessment model was built on the foundation of components degradation process. A simulation tactics based on variable structure modeling was given which is realized through Agent technique. A maintenance optimization example was given for the determination of maintenance opportunity which is used to support the formulation and improvement of maintenance support program for repairable system.


Construction And Utilization Of Simulation Meta-Model Based On Influence Diagram Game, Zhong Lin, Mingan Tong, Li Sheng Jan 2019

Construction And Utilization Of Simulation Meta-Model Based On Influence Diagram Game, Zhong Lin, Mingan Tong, Li Sheng

Journal of System Simulation

Abstract: To overcome the shortcomings of the meta-model, the dynamic influence diagram game is used as simulation meta-model. A construction process and the utilization for structured dynamic influence diagram game (DIDG) are presented. The necessary simulation data are gathered for the construction of a DIDG that presents the changes in simulation state with chance nodes. The decision alternatives and objectives of the decision problem are included in the DIDG as decision and utility nodes. The adversary’s action is represented by an explicit decision node in which case an influence diagram game results. The constructed DIDG is solved to …


Modeling And Simulation Of Airport Flight Flow Based On Cellular Automaton, Hongying Zhang, Xuwei Yang, Luo Qian Jan 2019

Modeling And Simulation Of Airport Flight Flow Based On Cellular Automaton, Hongying Zhang, Xuwei Yang, Luo Qian

Journal of System Simulation

Abstract: To increase the reliability of the airport scene traffic simulation model, the complex characteristics of scene traffic are researched. An improved model based on NS model is proposed. The influence of the stochastic factors on the taxiing process and the traffic characteristics at the intersection are considered, and the new cells are added to connect the two sections with different evolution rules. The state of the connected cells represents the occupancy of the next section. A large number of simulation experiments were processed, and the results show the goodness of fit between the simulation values and true ones increased …


Multi-Strategy Cooperative Evolutionary Pso Based On Cauchy Mutation Strategy, Yongji Wang, Tingting Su, Liu Lei Jan 2019

Multi-Strategy Cooperative Evolutionary Pso Based On Cauchy Mutation Strategy, Yongji Wang, Tingting Su, Liu Lei

Journal of System Simulation

Abstract: For improving the performance of particle swarm optimization (PSO) in optimization simulation, a multi-strategy cooperative evolutionary PSO based on Cauchy mutation strategy is proposed. The new algorithm divides the whole swarm into three sub-swarms. A part of particles is selected to Cauchy mutation with a certain probability, and the rest of particles adjust their exploitation and exploration by different evolutionary strategies (large-scale search strategy, local search strategy, and adaptive velocity updating strategy). The sub-swarms share their information to achieve cooperation. Three strategies are used to optimize three test functions, and the result shows the advantages …


Method Of Visualsimulation Of Rice Leaf Color, Hongyun Yang, Aizhen Sun, Wenji Yang, Huojiao He Jan 2019

Method Of Visualsimulation Of Rice Leaf Color, Hongyun Yang, Aizhen Sun, Wenji Yang, Huojiao He

Journal of System Simulation

Abstract: A color rendering method for rice leaves based on SPAD data distribution image was presented. Rice leaf image was collected and SPAD value was measured by field rice sample test. The relationship model between SPAD values and RGB value of leaf image was analyzed and constructed, and the R2 was 0.932 8, 0.833 1, 0.562 3 respectively. This showed that there was a correlation between SPAD and the red and green color of the leaf image. By the SPAD data distribution image, the spatial distribution of SPAD value on the leaf surface is described. The leaf surface color …


Message Passing Algorithm Through Particles On Factor Graph In Cooperative Positioning Network, Xinyue Fan, Wang Guan, Zhou Fei Jan 2019

Message Passing Algorithm Through Particles On Factor Graph In Cooperative Positioning Network, Xinyue Fan, Wang Guan, Zhou Fei

Journal of System Simulation

Abstract: Combining the sum-product algorithm with the factor graph can achieve cooperative positioning by a distributed manner. The sum-product algorithm is a message passing algorithm. However, the parameter method cannot meet the positioning needs because of the large error in the non-linear non-Gaussian environment. Therefore, this paper presents an algorithm to achieve message passing in the form of particle. The calculation of the message in the factor consists of summation and quadrature processes. The proposed method obtains the sum of messages by importance sampling, obtains the product of messages using Gibbs sampling. Particle-based information passing algorithm can simplify the complex …


Cell-Devs Social Interaction Modeling And Simulation For Emergency Evacuation Systems, Yanhong Wang, Wang Xia, Shaowei Wang Jan 2019

Cell-Devs Social Interaction Modeling And Simulation For Emergency Evacuation Systems, Yanhong Wang, Wang Xia, Shaowei Wang

Journal of System Simulation

Abstract: This paper aims to present a Cell-DEVS model for emergency evacuation systems, which behave uncertainty and are intricately driven by the social factors. The model introduces social interaction factors such as familiarity degrees, individual vision, communication and conduction, and velocity zones as the state variables, describing the relationship between the evacuees and environment, as well as the interactions with each other. The algorithm optimization enhances reality of simulation. The RESTful CD++ is applied as middleware to execute remote simulation. The results confirm the existence of social interaction. This work benefits to the architecture design, evacuation planning and …


Adaptive Feedback Elitist Teaching-Learning-Based Optimization Algorithm, Rongyu Li, Liang Dong, Guihong Qi Jan 2019

Adaptive Feedback Elitist Teaching-Learning-Based Optimization Algorithm, Rongyu Li, Liang Dong, Guihong Qi

Journal of System Simulation

Abstract: Elitist teaching-learning-based optimization (ETLBO) is a novel optimization algorithm based on the practical teaching-learning process of the class. An adaptive feedback elitist teaching-learning-based optimization (AFETLBO) algorithm is proposed to solve the problem of low precision and poor stability of the ETLBO. At the end of the learner phase, student can be divided into the top students and the inferior students dynamically by adding the adaptive feedback phase. In this phase, the inferior students should communicate with the teacher and enable themselves to be close to the teacher quickly so as to strengthen the convergence ability. The top students should …


Trajectory Planning And Interactive Simulation Software Design For Flight Vehicle With Specified Terminal Time, Mingwei Sun, Shunjian Ma, Zengqiang Chen, Chaofang Hu Jan 2019

Trajectory Planning And Interactive Simulation Software Design For Flight Vehicle With Specified Terminal Time, Mingwei Sun, Shunjian Ma, Zengqiang Chen, Chaofang Hu

Journal of System Simulation

Abstract: Specified terminal time is a special requirement in some path planning problems. It is difficult to solve in real time with specified time, angle and multiple no-fly zones considered. A practical path model is utilized, and a nonlinear optimization problem with respect to waypoints is reformulated. The requirements on time, angle and obstacle avoidance for original path planning problem are converted into constraints of the proposed optimization after geometrical relationships are identified. The optimization problem is established and met the form of sequential quadratic programming problem which is solved by SNOPT (Sparse Nonlinear OPTimizer) package. A computer-aid interactive simulation …


Coalescence Characteristics Of Droplets Containing Surfactants On Topographic Substrates, Xuemin Ye, Yuxi Lin, Lifang Lu, Chunxi Li Jan 2019

Coalescence Characteristics Of Droplets Containing Surfactants On Topographic Substrates, Xuemin Ye, Yuxi Lin, Lifang Lu, Chunxi Li

Journal of System Simulation

Abstract: The droplet motion evolution model was established based on the lubrication theory for two identical surfactant-containing droplets on the topographic substrate. The coalescing process of the droplets on topographic substrate was simulated, and the effects of spacing, wave number and base height on the characteristics of coalescing were examined. The results show that the two droplets meet and superimpose each other under the capillary force, and finally form a “new” droplet at tf. The dynamics of droplet over time are divided into five stages; while the surfactant concentration experiences the three stages in a short period; …


Image Classification Based On Sparse Autoencoder And Support Vector Machine, Liu Fang, Lixia Lu, Hongjuan Wang, Wang Xin Jan 2019

Image Classification Based On Sparse Autoencoder And Support Vector Machine, Liu Fang, Lixia Lu, Hongjuan Wang, Wang Xin

Journal of System Simulation

Abstract: A new algorithm of image classification based on the sparse autoencoder and the support vector machine was proposed in view of the drawbacks that the single layer sparse autoencoder for feature learning is easy to lose the deep abstract feature and the features lack the robustness. The deep sparse autoencoder is constructed to learn each image layer and the feature of each layer is automatically extracted. The each feature weights and the reorganized set of feature are obtained according to the feature weighting method. By combining the strong global search ability of genetic algorithm and the excellent performance of …


Broadband 2-D Doa Estimation Based On Continuous Sparse Recovery, Chenxi Wu, Zhang Min, Keren Wang Jan 2019

Broadband 2-D Doa Estimation Based On Continuous Sparse Recovery, Chenxi Wu, Zhang Min, Keren Wang

Journal of System Simulation

Abstract: For the problem of two dimensional underdetermined direction of arrival (2-D DOA) estimation, three parallel sparse arrays are designed and a novel DOA method based on continuous sparse recovery is proposed. The dimension of received data is reduced and the cross covariance matrix is vectorized to improve freedom degree. According to the objection function of the minimization issue based on total variation norm constraint, the space frequency is achieved by solving corresponding dual problem. The center frequency, azimuth and pitch angles are paired by capon method. Theoretical analysis shows the proposed method has a higher array aperture extension and …


Inputting Strategy Simulation Of Multi-Ramp Coordinated Control Signal For Urban Expressway, Mingbao Pang, Zemin Xia, Yanhai Luan Jan 2019

Inputting Strategy Simulation Of Multi-Ramp Coordinated Control Signal For Urban Expressway, Mingbao Pang, Zemin Xia, Yanhai Luan

Journal of System Simulation

Abstract: Based on the analysis of the driver's reaction when the urban expressway is in traffic jamming state and stated preference survey (SP) investigating, the key parameters' variation trends when the driving behavior adjusts and the possible path changing probability for a driver in each state are determined. A cellular automaton model of coordinated control section on urban expressway is established, where the driving behaviors are described accurately. The characteristics of traffic flow is discussed via the simulation experiments after inputting coordination control signals with different on-ramp numbers upstream of jamming point. The effects of each coordinated control modes on …


Open Circuit Fault Diagnosis Strategy For Switch Of Three Level Inverter, Yanxia Shen, Beibei Miao Jan 2019

Open Circuit Fault Diagnosis Strategy For Switch Of Three Level Inverter, Yanxia Shen, Beibei Miao

Journal of System Simulation

Abstract: Fault diagnosis of switch is the premise of reliable operation of three-level-inverter under the fault of the switch. Taking simple open circuit fault of the diode neutral point clamped (NPC) three level inverter as an example, the open circuit fault diagnosis method based on the combination of online and offline diagnoses is proposed. The fault phase is detected by the mean value of the bridge arm phase voltages. In the time domain, the fault switch tube is diagnosed by the maximum and minimum values of the load phase voltages. In the frequency domain, the amplitude of the fault signal …


Gams-Based Active Power Optimization With Reactive Power Compensation, Weiqing Sun, Ye Lei, Yiyun Tu Jan 2019

Gams-Based Active Power Optimization With Reactive Power Compensation, Weiqing Sun, Ye Lei, Yiyun Tu

Journal of System Simulation

Abstract: Based on the safe operation of the electric system, aiming at the problems of large power loss and high generation cost, it is unreasonable to schedule electricity through only one index, so a combined model of economic dispatch with reactive power optimization and a linearized model of unit commitment are proposed. The ideal point method changes multi-objective optimization problem which is combined with the generation cost and power loss into a single objective optimization problem and solved by GAMS. The case analysis for IEEE-39 bus system and a regional transmission network, by adjusting the generator active and reactive power …


Stability Analysis Of Post-Fault Power Angle Based On Relevance Vector Machine, Haiying Li, Zhuocheng Xue Jan 2019

Stability Analysis Of Post-Fault Power Angle Based On Relevance Vector Machine, Haiying Li, Zhuocheng Xue

Journal of System Simulation

Abstract: Energy interconnection has become a hot topic in the current research.With the large-scale of new energy into the grid, the safe operation of power system is facing new challenges. On line fast stability analysis is one of the effective ways to solve this problem. Traditional power system transient safety analysis method is difficult to adapt to the on-line analysis, and the further development of large data processing and machine learning provides a new way of thinking. The classification model of relevance vector machine (RVM) based on Bayesian framework is used to design a kind of power angle classification strategy. …


Simulation And Analysis Of Atmospheric Effects On Height Deriving From Insar, Xintian Wang, Guowang Jin, Xiong Xin, Hongmin Zhang, Xu Qing Jan 2019

Simulation And Analysis Of Atmospheric Effects On Height Deriving From Insar, Xintian Wang, Guowang Jin, Xiong Xin, Hongmin Zhang, Xu Qing

Journal of System Simulation

Abstract: The atmospheric phase delay caused by tropospheric water vapor (WV) is an important factor to the precision of repeat-pass mode interferometry synthetic aperture radar (InSAR). To study the WV effect quantitatively, the regulation of WV effect in repeat-pass InSAR is analyzed and the simulation scheme is designed in which the DEM and WV model is used to simulate InSAR interferogram and WV delay phase, and the derived height is analyzed. The experiment is performed by using systems and baseline parameters of SAR images of Henan;WV effected interferogram is simulated using DEM and vertical layered WV model; and the derived …


Trust Model And Simulation Of E-Commerce Based On Social Networks, Yu Zhen, Zhu Jie, Guicheng Shen Jan 2019

Trust Model And Simulation Of E-Commerce Based On Social Networks, Yu Zhen, Zhu Jie, Guicheng Shen

Journal of System Simulation

Abstract: In the current e-commerce industry, users need to check for the historical evaluation of the commodity before buying goods mostly, but false recommendations and massive redundancy recommendation problem which widely exists at present seriously affect the effectiveness and accuracy of users’ obtaining recommendations. For getting trust in e-commerce transactions, an e-commerce trust model SNTrust based on social networks is proposed. In SNTrust model, each user maintains a trusted social network set; a topological structure of the user information diffusion in the social network is described in the model, and the recommendation node trust is introduced to measure its credibility, …


Quadrotor Attitude Control Based On An Improved Adrc, Wang Biao, Chaoying Tang, Daqing Kong Jan 2019

Quadrotor Attitude Control Based On An Improved Adrc, Wang Biao, Chaoying Tang, Daqing Kong

Journal of System Simulation

Abstract: An improved attitude control scheme for the quadrotor is proposed based on active disturbance rejection control (ADRC). The attitude dynamics of the quadrotor is modelled and analysed. The influence of actuator characteristics is discussed to establish an extended state observer (ESO). Based on it, the ESO is compensated by the delay unit and its discrete state equations are given. Nonlinear function of previous studies is used to construct nonlinear state error feedback (NLSEF). The simulation results show that the ESO with compensation of the delay unit gets better estimation of disturbance and compensates to disturbance better than the ESO …


Research On Concession Period Performance Of Highway Ppp Project Based On Pavement Maintenance, Zhang Hong, Rongbei Zheng, Wenshan Qiao Jan 2019

Research On Concession Period Performance Of Highway Ppp Project Based On Pavement Maintenance, Zhang Hong, Rongbei Zheng, Wenshan Qiao

Journal of System Simulation

Abstract: There are long-term dynamic and interactive relationships among highway pavement performance, user satisfaction, maintenance costs and profits, government satisfaction and related decisions in the life cycle pavement maintenance. Based on analyses of dynamic impacts and complexity of stakeholders’ behaviors around the highway pavement maintenance, a system dynamics (SD) model of the concession period performance for the highway public-private-partnership (PPP) project is established. Based on simulation experimental analysis of an example, validation and application of the proposed SD model are illustrated. Through sensitivity analysis, the influences of different stakeholders such as government, private investors, and users on the concession …